diff --git a/go.mod b/go.mod
index 14e8a46a9..d9ae9f13e 100644
--- a/go.mod
+++ b/go.mod
@@ -3,7 +3,7 @@ module github.com/emer/axon/v2
 go 1.22
 
 require (
-	cogentcore.org/core v0.3.8-0.20250107202432-e0c4c10448e1
+	cogentcore.org/core v0.3.8-0.20250113105110-b73be80edead
 	cogentcore.org/lab v0.0.0-20250109203708-c742f9552551
 	github.com/anthonynsimon/bild v0.13.0
 	github.com/cogentcore/yaegi v0.0.0-20240724064145-e32a03faad56
diff --git a/go.sum b/go.sum
index d5b7635d6..fe99ebfc4 100644
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,5 @@
-cogentcore.org/core v0.3.8-0.20250107202432-e0c4c10448e1 h1:rLT0EDrIQKABTyChQNTgh7qfUizUCYVywhJTAAvueU4=
-cogentcore.org/core v0.3.8-0.20250107202432-e0c4c10448e1/go.mod h1:Ipnb14B+l0qLzjvcvCIhnDucV9H9RyuqS4knZz5kB8A=
+cogentcore.org/core v0.3.8-0.20250113105110-b73be80edead h1:aBcVq6+4XbhphORwy1oyZUGbTSkKMkzyxKnM5Oo/O1c=
+cogentcore.org/core v0.3.8-0.20250113105110-b73be80edead/go.mod h1:Ipnb14B+l0qLzjvcvCIhnDucV9H9RyuqS4knZz5kB8A=
 cogentcore.org/lab v0.0.0-20250109203708-c742f9552551 h1:aHaTWuqrsVKnwrcPACwAGy8v0KN5bCxgDqcwfzjtsmA=
 cogentcore.org/lab v0.0.0-20250109203708-c742f9552551/go.mod h1:cFjKEyMK/eCST7x6sGCGjC12iY+/vcgZime7ASFnM/k=
 github.com/Bios-Marcel/wastebasket v0.0.4-0.20240213135800-f26f1ae0a7c4 h1:6lx9xzJAhdjq0LvVfbITeC3IH9Fzvo1aBahyPu2FuG8=
diff --git a/sims/bgdorsal/bg-dorsal.go b/sims/bgdorsal/bg-dorsal.go
index fad7c9c37..ccdd7c760 100644
--- a/sims/bgdorsal/bg-dorsal.go
+++ b/sims/bgdorsal/bg-dorsal.go
@@ -138,6 +138,7 @@ func (ss *Sim) Run() {
 	ss.RandSeeds.Init(100) // max 100 runs
 	ss.InitRandSeed(0)
 	if ss.Config.Run.GPU {
+		gpu.SelectAdapter = ss.Config.Run.GPUDevice
 		axon.GPUInit()
 		axon.UseGPU = true
 	}
diff --git a/sims/bgdorsal/config.go b/sims/bgdorsal/config.go
index c1745d516..f9a2a7eec 100644
--- a/sims/bgdorsal/config.go
+++ b/sims/bgdorsal/config.go
@@ -72,6 +72,9 @@ type RunConfig struct {
 	// GPU uses the GPU for computation.
 	GPU bool `default:"true"`
 
+	// GPUDevice selects the gpu device to use.
+	GPUDevice int
+
 	// NData is the number of data-parallel items to process in parallel per trial.
 	// Is significantly faster for both CPU and GPU.  Results in an effective
 	// mini-batch of learning.
diff --git a/sims/bgventral/bg-ventral.go b/sims/bgventral/bg-ventral.go
index 9d23692be..6822d24c4 100644
--- a/sims/bgventral/bg-ventral.go
+++ b/sims/bgventral/bg-ventral.go
@@ -19,6 +19,7 @@ import (
 	"cogentcore.org/core/cli"
 	"cogentcore.org/core/core"
 	"cogentcore.org/core/enums"
+	"cogentcore.org/core/gpu"
 	"cogentcore.org/core/icons"
 	"cogentcore.org/core/math32"
 	"cogentcore.org/core/tree"
@@ -135,6 +136,7 @@ func (ss *Sim) Run() {
 	ss.RandSeeds.Init(100) // max 100 runs
 	ss.InitRandSeed(0)
 	if ss.Config.Run.GPU {
+		gpu.SelectAdapter = ss.Config.Run.GPUDevice
 		axon.GPUInit()
 		axon.UseGPU = true
 	}
diff --git a/sims/bgventral/config.go b/sims/bgventral/config.go
index 4f94bf94d..9f69e9ba2 100644
--- a/sims/bgventral/config.go
+++ b/sims/bgventral/config.go
@@ -62,6 +62,9 @@ type RunConfig struct {
 	// GPU uses the GPU for computation; only for testing in this model -- not faster.
 	GPU bool `default:"true"`
 
+	// GPUDevice selects the gpu device to use.
+	GPUDevice int
+
 	// NData is the number of data-parallel items to process in parallel per trial.
 	// Is significantly faster for both CPU and GPU.  Results in an effective
 	// mini-batch of learning.
diff --git a/sims/choose/choose.go b/sims/choose/choose.go
index ff1a8865f..3f80fd65d 100644
--- a/sims/choose/choose.go
+++ b/sims/choose/choose.go
@@ -18,6 +18,7 @@ import (
 	"cogentcore.org/core/cli"
 	"cogentcore.org/core/core"
 	"cogentcore.org/core/enums"
+	"cogentcore.org/core/gpu"
 	"cogentcore.org/core/icons"
 	"cogentcore.org/core/math32"
 	"cogentcore.org/core/tree"
@@ -138,6 +139,7 @@ func (ss *Sim) Run() {
 	ss.RandSeeds.Init(100) // max 100 runs
 	ss.InitRandSeed(0)
 	if ss.Config.Run.GPU {
+		gpu.SelectAdapter = ss.Config.Run.GPUDevice
 		axon.GPUInit()
 		axon.UseGPU = true
 	}
diff --git a/sims/choose/config.go b/sims/choose/config.go
index c9a5a9db8..afe339a41 100644
--- a/sims/choose/config.go
+++ b/sims/choose/config.go
@@ -89,6 +89,9 @@ type RunConfig struct {
 	// GPU uses the GPU for computation: not faster in this case.
 	GPU bool `default:"true"`
 
+	// GPUDevice selects the gpu device to use.
+	GPUDevice int
+
 	// NData is the number of data-parallel items to process in parallel per trial.
 	// Is significantly faster for both CPU and GPU.  Results in an effective
 	// mini-batch of learning.
diff --git a/sims/deepfsa/config.go b/sims/deepfsa/config.go
index 79f89866c..486942598 100644
--- a/sims/deepfsa/config.go
+++ b/sims/deepfsa/config.go
@@ -72,6 +72,9 @@ type RunConfig struct {
 	// small models if NData ~16.
 	GPU bool `default:"true"`
 
+	// GPUDevice selects the gpu device to use.
+	GPUDevice int
+
 	// NData is the number of data-parallel items to process in parallel per trial.
 	// Is significantly faster for both CPU and GPU.  Results in an effective
 	// mini-batch of learning.
diff --git a/sims/deepfsa/deep-fsa.go b/sims/deepfsa/deep-fsa.go
index 1d8b23060..2f3aea7e0 100644
--- a/sims/deepfsa/deep-fsa.go
+++ b/sims/deepfsa/deep-fsa.go
@@ -17,6 +17,7 @@ import (
 	"cogentcore.org/core/cli"
 	"cogentcore.org/core/core"
 	"cogentcore.org/core/enums"
+	"cogentcore.org/core/gpu"
 	"cogentcore.org/core/icons"
 	"cogentcore.org/core/math32"
 	"cogentcore.org/core/tree"
@@ -133,6 +134,7 @@ func (ss *Sim) Run() {
 	ss.RandSeeds.Init(100) // max 100 runs
 	ss.InitRandSeed(0)
 	if ss.Config.Run.GPU {
+		gpu.SelectAdapter = ss.Config.Run.GPUDevice
 		axon.GPUInit()
 		axon.UseGPU = true
 	}
diff --git a/sims/deepmove/config.go b/sims/deepmove/config.go
index 2cd51c35f..fc5377ed5 100644
--- a/sims/deepmove/config.go
+++ b/sims/deepmove/config.go
@@ -59,6 +59,9 @@ type RunConfig struct { //types:add
 	// small models if NData ~16.
 	GPU bool `default:"true"`
 
+	// GPUDevice selects the gpu device to use.
+	GPUDevice int
+
 	// NData is the number of data-parallel items to process in parallel per trial.
 	// Is significantly faster for both CPU and GPU.  Results in an effective
 	// mini-batch of learning.
diff --git a/sims/deepmove/deep-move.go b/sims/deepmove/deep-move.go
index 876217d22..9db242364 100644
--- a/sims/deepmove/deep-move.go
+++ b/sims/deepmove/deep-move.go
@@ -16,6 +16,7 @@ import (
 	"cogentcore.org/core/cli"
 	"cogentcore.org/core/core"
 	"cogentcore.org/core/enums"
+	"cogentcore.org/core/gpu"
 	"cogentcore.org/core/icons"
 	"cogentcore.org/core/math32"
 	"cogentcore.org/core/math32/vecint"
@@ -136,6 +137,7 @@ func (ss *Sim) Run() {
 	ss.RandSeeds.Init(100) // max 100 runs
 	ss.InitRandSeed(0)
 	if ss.Config.Run.GPU {
+		gpu.SelectAdapter = ss.Config.Run.GPUDevice
 		axon.GPUInit()
 		axon.UseGPU = true
 	}
diff --git a/sims/deepmusic/config.go b/sims/deepmusic/config.go
index 41fcd49fe..48ad0e34a 100644
--- a/sims/deepmusic/config.go
+++ b/sims/deepmusic/config.go
@@ -68,6 +68,9 @@ type RunConfig struct { //types:add
 	// small models if NData ~16.
 	GPU bool `default:"true"`
 
+	// GPUDevice selects the gpu device to use.
+	GPUDevice int
+
 	// NData is the number of data-parallel items to process in parallel per trial.
 	// Is significantly faster for both CPU and GPU.  Results in an effective
 	// mini-batch of learning.
diff --git a/sims/deepmusic/deep-music.go b/sims/deepmusic/deep-music.go
index 05f634297..b4c340d33 100644
--- a/sims/deepmusic/deep-music.go
+++ b/sims/deepmusic/deep-music.go
@@ -17,6 +17,7 @@ import (
 	"cogentcore.org/core/cli"
 	"cogentcore.org/core/core"
 	"cogentcore.org/core/enums"
+	"cogentcore.org/core/gpu"
 	"cogentcore.org/core/icons"
 	"cogentcore.org/core/math32"
 	"cogentcore.org/core/tree"
@@ -138,6 +139,7 @@ func (ss *Sim) Run() {
 	ss.RandSeeds.Init(100) // max 100 runs
 	ss.InitRandSeed(0)
 	if ss.Config.Run.GPU {
+		gpu.SelectAdapter = ss.Config.Run.GPUDevice
 		axon.GPUInit()
 		axon.UseGPU = true
 	}
diff --git a/sims/hip/config.go b/sims/hip/config.go
index 85948c670..337dc3e5e 100644
--- a/sims/hip/config.go
+++ b/sims/hip/config.go
@@ -75,6 +75,9 @@ type RunConfig struct {
 	// small models if NData ~16.
 	GPU bool `default:"true"`
 
+	// GPUDevice selects the gpu device to use.
+	GPUDevice int
+
 	// NData is the number of data-parallel items to process in parallel per trial.
 	// Is significantly faster for both CPU and GPU.  Results in an effective
 	// mini-batch of learning.
diff --git a/sims/hip/hip.go b/sims/hip/hip.go
index c5805c172..22baca577 100644
--- a/sims/hip/hip.go
+++ b/sims/hip/hip.go
@@ -15,6 +15,7 @@ import (
 	"cogentcore.org/core/cli"
 	"cogentcore.org/core/core"
 	"cogentcore.org/core/enums"
+	"cogentcore.org/core/gpu"
 	"cogentcore.org/core/icons"
 	"cogentcore.org/core/math32"
 	"cogentcore.org/core/tree"
@@ -133,6 +134,7 @@ func (ss *Sim) Run() {
 	ss.RandSeeds.Init(100) // max 100 runs
 	ss.InitRandSeed(0)
 	if ss.Config.Run.GPU {
+		gpu.SelectAdapter = ss.Config.Run.GPUDevice
 		axon.GPUInit()
 		axon.UseGPU = true
 	}
diff --git a/sims/inhib/config.go b/sims/inhib/config.go
index 3f1d6e2a2..09a30dad9 100644
--- a/sims/inhib/config.go
+++ b/sims/inhib/config.go
@@ -53,6 +53,9 @@ type RunConfig struct {
 	// GPU uses the GPU for computation, largely for testing purposes here.
 	GPU bool `default:"false"`
 
+	// GPUDevice selects the gpu device to use.
+	GPUDevice int
+
 	// Trials is the total number of trials of different random patterns to generate.
 	Trials int `default:"10"`
 
diff --git a/sims/inhib/inhib.go b/sims/inhib/inhib.go
index b7c836ff3..4a15f006d 100644
--- a/sims/inhib/inhib.go
+++ b/sims/inhib/inhib.go
@@ -17,6 +17,7 @@ import (
 	"cogentcore.org/core/cli"
 	"cogentcore.org/core/core"
 	"cogentcore.org/core/enums"
+	"cogentcore.org/core/gpu"
 	"cogentcore.org/core/icons"
 	"cogentcore.org/core/math32"
 	"cogentcore.org/core/tree"
@@ -134,6 +135,7 @@ func (ss *Sim) Run() {
 	ss.RandSeeds.Init(100) // max 100 runs
 	ss.InitRandSeed(0)
 	if ss.Config.Run.GPU {
+		gpu.SelectAdapter = ss.Config.Run.GPUDevice
 		axon.GPUInit()
 		axon.UseGPU = true
 	}
diff --git a/sims/mpi/config.go b/sims/mpi/config.go
index b5537e09c..d9d75194b 100644
--- a/sims/mpi/config.go
+++ b/sims/mpi/config.go
@@ -50,6 +50,9 @@ type RunConfig struct {
 	// small models if NData ~16.
 	GPU bool `default:"true"`
 
+	// GPUDevice selects the gpu device to use.
+	GPUDevice int
+
 	// NData is the number of data-parallel items to process in parallel per trial.
 	// Is significantly faster for both CPU and GPU.  Results in an effective
 	// mini-batch of learning.
diff --git a/sims/mpi/mpi.go b/sims/mpi/mpi.go
index 1f9ce96f2..c51e0e86f 100644
--- a/sims/mpi/mpi.go
+++ b/sims/mpi/mpi.go
@@ -21,6 +21,7 @@ import (
 	"cogentcore.org/core/cli"
 	"cogentcore.org/core/core"
 	"cogentcore.org/core/enums"
+	"cogentcore.org/core/gpu"
 	"cogentcore.org/core/icons"
 	"cogentcore.org/core/math32"
 	"cogentcore.org/core/tree"
@@ -144,6 +145,7 @@ func (ss *Sim) Run() {
 	ss.RandSeeds.Init(100) // max 100 runs
 	ss.InitRandSeed(0)
 	if ss.Config.Run.GPU {
+		gpu.SelectAdapter = ss.Config.Run.GPUDevice
 		axon.GPUInit()
 		axon.UseGPU = true
 	}
diff --git a/sims/objrec/config.go b/sims/objrec/config.go
index 444aebb65..d9860566c 100644
--- a/sims/objrec/config.go
+++ b/sims/objrec/config.go
@@ -71,6 +71,9 @@ type RunConfig struct {
 	// small models if NData ~16.
 	GPU bool `default:"true"`
 
+	// GPUDevice selects the gpu device to use.
+	GPUDevice int
+
 	// NData is the number of data-parallel items to process in parallel per trial.
 	// Is significantly faster for both CPU and GPU.  Results in an effective
 	// mini-batch of learning.
@@ -102,7 +105,7 @@ type RunConfig struct {
 	PlusCycles int `default:"50"`
 
 	// CaBinCycles is the number of cycles per CaBin: how fine-grained the synaptic Ca is.
-	CaBinCycles int `default:"25"`
+	CaBinCycles int `default:"25"` // no diff for 25 vs. 10
 
 	// NZero is how many perfect, zero-error epochs before stopping a Run.
 	NZero int `default:"2"`
diff --git a/sims/objrec/objrec.go b/sims/objrec/objrec.go
index a5f635051..c0fcb85da 100644
--- a/sims/objrec/objrec.go
+++ b/sims/objrec/objrec.go
@@ -18,6 +18,7 @@ import (
 	"cogentcore.org/core/cli"
 	"cogentcore.org/core/core"
 	"cogentcore.org/core/enums"
+	"cogentcore.org/core/gpu"
 	"cogentcore.org/core/icons"
 	"cogentcore.org/core/math32"
 	"cogentcore.org/core/tree"
@@ -139,6 +140,7 @@ func (ss *Sim) Run() {
 	ss.RandSeeds.Init(100) // max 100 runs
 	ss.InitRandSeed(0)
 	if ss.Config.Run.GPU {
+		gpu.SelectAdapter = ss.Config.Run.GPUDevice
 		axon.GPUInit()
 		axon.UseGPU = true
 	}
diff --git a/sims/objrec/params.go b/sims/objrec/params.go
index d1efdd934..d07f6caa2 100644
--- a/sims/objrec/params.go
+++ b/sims/objrec/params.go
@@ -88,7 +88,7 @@ var PathParams = axon.PathSheets{
 				pt.Learn.DWt.SubMean = 1     // 1 -- faster if 0 until 20 epc -- prevents sig amount of late deterioration
 				pt.SWts.Adapt.LRate = 0.0001 // 0.005 == .1 == .01
 				pt.SWts.Init.SPct = 1        // 1 >= lower (trace-v11)
-				pt.Learn.DWt.CaPScale = 0.95 // trace: 0.95 resists late hogging
+				pt.Learn.DWt.CaPScale = 0.95 // 0.95 essential vs. 1.0
 				// pt.Learn.DWt.Trace.SetBool(false) // no trace is faster!
 			}},
 		{Sel: ".BackPath", Doc: "top-down back-pathways MUST have lower relative weight scale, otherwise network hallucinates -- smaller as network gets bigger",
diff --git a/sims/pfcmaint/config.go b/sims/pfcmaint/config.go
index c3009914e..bfb6c9524 100644
--- a/sims/pfcmaint/config.go
+++ b/sims/pfcmaint/config.go
@@ -65,6 +65,9 @@ type RunConfig struct {
 	// GPU uses the GPU for computation; only for testing in this model -- not faster.
 	GPU bool `default:"true"`
 
+	// GPUDevice selects the gpu device to use.
+	GPUDevice int
+
 	// NData is the number of data-parallel items to process in parallel per trial.
 	// Is significantly faster for both CPU and GPU.  Results in an effective
 	// mini-batch of learning.
diff --git a/sims/pfcmaint/pfcmaint.go b/sims/pfcmaint/pfcmaint.go
index a02c965b0..c58d25f2a 100644
--- a/sims/pfcmaint/pfcmaint.go
+++ b/sims/pfcmaint/pfcmaint.go
@@ -16,6 +16,7 @@ import (
 	"cogentcore.org/core/base/reflectx"
 	"cogentcore.org/core/core"
 	"cogentcore.org/core/enums"
+	"cogentcore.org/core/gpu"
 	"cogentcore.org/core/icons"
 	"cogentcore.org/core/math32"
 	"cogentcore.org/core/tree"
@@ -124,6 +125,7 @@ func (ss *Sim) Run() {
 	ss.RandSeeds.Init(100) // max 100 runs
 	ss.InitRandSeed(0)
 	if ss.Config.Run.GPU {
+		gpu.SelectAdapter = ss.Config.Run.GPUDevice
 		axon.GPUInit()
 		axon.UseGPU = true
 	}
diff --git a/sims/pvlv/config.go b/sims/pvlv/config.go
index 46cf91a51..52e0af39d 100644
--- a/sims/pvlv/config.go
+++ b/sims/pvlv/config.go
@@ -71,6 +71,9 @@ type RunConfig struct {
 	// GPU uses the GPU for computation: not faster in this case.
 	GPU bool `default:"false"`
 
+	// GPUDevice selects the gpu device to use.
+	GPUDevice int
+
 	// NThreads is the number of parallel threads for CPU computation;
 	// 0 = use default.
 	NThreads int `default:"0"`
diff --git a/sims/pvlv/pvlv.go b/sims/pvlv/pvlv.go
index 945acbbd9..9e0301aed 100644
--- a/sims/pvlv/pvlv.go
+++ b/sims/pvlv/pvlv.go
@@ -19,6 +19,7 @@ import (
 	"cogentcore.org/core/cli"
 	"cogentcore.org/core/core"
 	"cogentcore.org/core/enums"
+	"cogentcore.org/core/gpu"
 	"cogentcore.org/core/icons"
 	"cogentcore.org/core/math32"
 	"cogentcore.org/core/tree"
@@ -132,6 +133,7 @@ func (ss *Sim) Run() {
 	ss.RandSeeds.Init(100) // max 100 runs
 	ss.InitRandSeed(0)
 	if ss.Config.Run.GPU {
+		gpu.SelectAdapter = ss.Config.Run.GPUDevice
 		axon.GPUInit()
 		axon.UseGPU = true
 	}
diff --git a/sims/ra25/config.go b/sims/ra25/config.go
index 0b500e665..77de2d40a 100644
--- a/sims/ra25/config.go
+++ b/sims/ra25/config.go
@@ -52,6 +52,9 @@ type RunConfig struct {
 	// small models if NData ~16.
 	GPU bool `default:"true"`
 
+	// GPUDevice selects the gpu device to use.
+	GPUDevice int
+
 	// NData is the number of data-parallel items to process in parallel per trial.
 	// Is significantly faster for both CPU and GPU.  Results in an effective
 	// mini-batch of learning.
diff --git a/sims/ra25/ra25.go b/sims/ra25/ra25.go
index db693074d..2ccbd36e1 100644
--- a/sims/ra25/ra25.go
+++ b/sims/ra25/ra25.go
@@ -147,6 +147,8 @@ func (ss *Sim) Run() {
 	ss.RandSeeds.Init(100) // max 100 runs
 	ss.InitRandSeed(0)
 	if ss.Config.Run.GPU {
+		// gpu.DebugAdapter = true
+		gpu.SelectAdapter = ss.Config.Run.GPUDevice
 		axon.GPUInit()
 		axon.UseGPU = true
 	}
diff --git a/sims/ra25x/config.go b/sims/ra25x/config.go
index d72555bfe..a180ecb90 100644
--- a/sims/ra25x/config.go
+++ b/sims/ra25x/config.go
@@ -50,6 +50,9 @@ type RunConfig struct {
 	// small models if NData ~16.
 	GPU bool `default:"true"`
 
+	// GPUDevice selects the gpu device to use.
+	GPUDevice int
+
 	// NData is the number of data-parallel items to process in parallel per trial.
 	// Is significantly faster for both CPU and GPU.  Results in an effective
 	// mini-batch of learning.
diff --git a/sims/ra25x/ra25x.go b/sims/ra25x/ra25x.go
index 33fb58a90..307d81a20 100644
--- a/sims/ra25x/ra25x.go
+++ b/sims/ra25x/ra25x.go
@@ -21,6 +21,7 @@ import (
 	"cogentcore.org/core/cli"
 	"cogentcore.org/core/core"
 	"cogentcore.org/core/enums"
+	"cogentcore.org/core/gpu"
 	"cogentcore.org/core/icons"
 	"cogentcore.org/core/math32"
 	"cogentcore.org/core/tree"
@@ -144,6 +145,7 @@ func (ss *Sim) Run() {
 	ss.RandSeeds.Init(100) // max 100 runs
 	ss.InitRandSeed(0)
 	if ss.Config.Run.GPU {
+		gpu.SelectAdapter = ss.Config.Run.GPUDevice
 		axon.GPUInit()
 		axon.UseGPU = true
 	}
diff --git a/sims/rl/config.go b/sims/rl/config.go
index eedfd79ae..91e3a8e55 100644
--- a/sims/rl/config.go
+++ b/sims/rl/config.go
@@ -49,6 +49,9 @@ type RunConfig struct {
 	// GPU uses the GPU for computation; only for testing in this model -- not faster.
 	GPU bool `default:"false"`
 
+	// GPUDevice selects the gpu device to use.
+	GPUDevice int
+
 	// NData is the number of data-parallel items to process in parallel per trial.
 	// Is significantly faster for both CPU and GPU.  Results in an effective
 	// mini-batch of learning.
diff --git a/sims/rl/rl.go b/sims/rl/rl.go
index b10a6470d..7af9455b3 100644
--- a/sims/rl/rl.go
+++ b/sims/rl/rl.go
@@ -18,6 +18,7 @@ import (
 	"cogentcore.org/core/cli"
 	"cogentcore.org/core/core"
 	"cogentcore.org/core/enums"
+	"cogentcore.org/core/gpu"
 	"cogentcore.org/core/icons"
 	"cogentcore.org/core/math32"
 	"cogentcore.org/core/tree"
@@ -131,6 +132,7 @@ func (ss *Sim) Run() {
 	ss.RandSeeds.Init(100) // max 100 runs
 	ss.InitRandSeed(0)
 	if ss.Config.Run.GPU {
+		gpu.SelectAdapter = ss.Config.Run.GPUDevice
 		axon.GPUInit()
 		axon.UseGPU = true
 	}
diff --git a/sims/vspatch/config.go b/sims/vspatch/config.go
index 559d1243f..63d8cbb7e 100644
--- a/sims/vspatch/config.go
+++ b/sims/vspatch/config.go
@@ -58,6 +58,9 @@ type RunConfig struct {
 	// GPU uses the GPU for computation; only for testing in this model -- not faster.
 	GPU bool `default:"true"`
 
+	// GPUDevice selects the gpu device to use.
+	GPUDevice int
+
 	// NData is the number of data-parallel items to process in parallel per trial.
 	// Is significantly faster for both CPU and GPU.  Results in an effective
 	// mini-batch of learning.
diff --git a/sims/vspatch/vspatch.go b/sims/vspatch/vspatch.go
index dc6a6d5c8..60609f5cd 100644
--- a/sims/vspatch/vspatch.go
+++ b/sims/vspatch/vspatch.go
@@ -18,6 +18,7 @@ import (
 	"cogentcore.org/core/cli"
 	"cogentcore.org/core/core"
 	"cogentcore.org/core/enums"
+	"cogentcore.org/core/gpu"
 	"cogentcore.org/core/icons"
 	"cogentcore.org/core/math32"
 	"cogentcore.org/core/tree"
@@ -136,6 +137,7 @@ func (ss *Sim) Run() {
 	ss.RandSeeds.Init(100) // max 100 runs
 	ss.InitRandSeed(0)
 	if ss.Config.Run.GPU {
+		gpu.SelectAdapter = ss.Config.Run.GPUDevice
 		axon.GPUInit()
 		axon.UseGPU = true
 	}