diff --git a/pkg/system/capabilities.go b/pkg/system/capabilities.go
index bbff3b8e2..9141d5929 100644
--- a/pkg/system/capabilities.go
+++ b/pkg/system/capabilities.go
@@ -132,29 +132,32 @@ func (s *SystemState) getSystemCapabilities() string {
 		}
 	}
 
-	if cuda13DirExists {
-		s.systemCapabilities = nvidiaCuda13
-		return s.systemCapabilities
-	}
-
-	if cuda12DirExists {
-		s.systemCapabilities = nvidiaCuda12
-		return s.systemCapabilities
-	}
-
+	// No GPU detected → default capability
 	if s.GPUVendor == "" {
 		xlog.Info("Default capability (no GPU detected)", "env", capabilityEnv)
 		s.systemCapabilities = defaultCapability
 		return s.systemCapabilities
 	}
 
-	// If vram is less than 4GB, let's default to CPU but warn the user that they can override that via env
+	// GPU detected but insufficient VRAM → default with warning
 	if s.VRAM <= 4*1024*1024*1024 {
 		xlog.Warn("VRAM is less than 4GB, defaulting to CPU", "env", capabilityEnv)
 		s.systemCapabilities = defaultCapability
 		return s.systemCapabilities
 	}
 
+	// CUDA directories refine capability only for NVIDIA GPUs
+	if s.GPUVendor == Nvidia {
+		if cuda13DirExists {
+			s.systemCapabilities = nvidiaCuda13
+			return s.systemCapabilities
+		}
+		if cuda12DirExists {
+			s.systemCapabilities = nvidiaCuda12
+			return s.systemCapabilities
+		}
+	}
+
 	s.systemCapabilities = s.GPUVendor
 	return s.systemCapabilities
 }
diff --git a/pkg/system/capabilities_test.go b/pkg/system/capabilities_test.go
new file mode 100644
index 000000000..a267cf611
--- /dev/null
+++ b/pkg/system/capabilities_test.go
@@ -0,0 +1,129 @@
+package system
+
+import (
+	"os"
+	"runtime"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("getSystemCapabilities", func() {
+	const eightGB = 8 * 1024 * 1024 * 1024
+	const twoGB = 2 * 1024 * 1024 * 1024
+
+	var (
+		origEnv    string
+		origCuda12 bool
+		origCuda13 bool
+	)
+
+	BeforeEach(func() {
+		if runtime.GOOS == "darwin" {
+			Skip("darwin short-circuits before reaching CUDA logic")
+		}
+
+		origEnv = os.Getenv(capabilityEnv)
+		os.Unsetenv(capabilityEnv)
+
+		origCuda12 = cuda12DirExists
+		origCuda13 = cuda13DirExists
+	})
+
+	AfterEach(func() {
+		cuda12DirExists = origCuda12
+		cuda13DirExists = origCuda13
+
+		if origEnv != "" {
+			os.Setenv(capabilityEnv, origEnv)
+		}
+	})
+
+	type testCase struct {
+		gpuVendor      string
+		vram           uint64
+		cuda12         bool
+		cuda13         bool
+		wantCapability string
+		wantTokens     []string
+	}
+
+	DescribeTable("capability detection",
+		func(tc testCase) {
+			cuda12DirExists = tc.cuda12
+			cuda13DirExists = tc.cuda13
+
+			s := &SystemState{
+				GPUVendor: tc.gpuVendor,
+				VRAM:      tc.vram,
+			}
+
+			Expect(s.getSystemCapabilities()).To(Equal(tc.wantCapability))
+			Expect(s.BackendPreferenceTokens()).To(Equal(tc.wantTokens))
+		},
+		Entry("CUDA dir present but no GPU", testCase{
+			gpuVendor:      "",
+			vram:           0,
+			cuda12:         true,
+			cuda13:         false,
+			wantCapability: "default",
+			wantTokens:     []string{"cpu"},
+		}),
+		Entry("CUDA 12 with NVIDIA GPU", testCase{
+			gpuVendor:      Nvidia,
+			vram:           eightGB,
+			cuda12:         true,
+			cuda13:         false,
+			wantCapability: "nvidia-cuda-12",
+			wantTokens:     []string{"cuda", "vulkan", "cpu"},
+		}),
+		Entry("CUDA 13 with NVIDIA GPU", testCase{
+			gpuVendor:      Nvidia,
+			vram:           eightGB,
+			cuda12:         false,
+			cuda13:         true,
+			wantCapability: "nvidia-cuda-13",
+			wantTokens:     []string{"cuda", "vulkan", "cpu"},
+		}),
+		Entry("Both CUDA dirs with NVIDIA GPU prefers 13", testCase{
+			gpuVendor:      Nvidia,
+			vram:           eightGB,
+			cuda12:         true,
+			cuda13:         true,
+			wantCapability: "nvidia-cuda-13",
+			wantTokens:     []string{"cuda", "vulkan", "cpu"},
+		}),
+		Entry("CUDA dir with AMD GPU ignored", testCase{
+			gpuVendor:      AMD,
+			vram:           eightGB,
+			cuda12:         true,
+			cuda13:         false,
+			wantCapability: "amd",
+			wantTokens:     []string{"rocm", "hip", "vulkan", "cpu"},
+		}),
+		Entry("No CUDA dir and no GPU", testCase{
+			gpuVendor:      "",
+			vram:           0,
+			cuda12:         false,
+			cuda13:         false,
+			wantCapability: "default",
+			wantTokens:     []string{"cpu"},
+		}),
+		Entry("No CUDA dir with NVIDIA GPU", testCase{
+			gpuVendor:      Nvidia,
+			vram:           eightGB,
+			cuda12:         false,
+			cuda13:         false,
+			wantCapability: "nvidia",
+			wantTokens:     []string{"cuda", "vulkan", "cpu"},
+		}),
+		Entry("CUDA dir with NVIDIA GPU but low VRAM", testCase{
+			gpuVendor:      Nvidia,
+			vram:           twoGB,
+			cuda12:         true,
+			cuda13:         false,
+			wantCapability: "default",
+			wantTokens:     []string{"cpu"},
+		}),
+	)
+})
diff --git a/pkg/system/system_suite_test.go b/pkg/system/system_suite_test.go
new file mode 100644
index 000000000..9c9fded36
--- /dev/null
+++ b/pkg/system/system_suite_test.go
@@ -0,0 +1,13 @@
+package system
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+func TestSystem(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "System test suite")
+}