20GB limit ? Cannot test RTX 6000 PRO with 96GB

[tonycstech]

Cannot test RTX 6000 PRO with 96GB

[galkinvv]

No specific limit known, unless imposed by the driver.

Here 29GB is allocated for 5090: https://www.overclock.net/attachments/1766265953822-png.2743634/
Full 32GB is not allocated on RTX5090, some percent is left to OS to avoid it hangs.

Which OS? How exactly it behaves - hang/error message? Rename to memtest-vulkan-verbose and show its output (more detailed).

From my experience - for windows a swap file with size similar to VRAM is needed, otherwise driver sometimes forbids huge allocations.
So, if on Windows, try making huge swap, it won't be used, but needed.

And when huge allocations are forbidden - memtest_vulkan automatically tries to auto-select lower VRAM size. The auto-selection algorithm is bad (linear, each attempt is 0.5GB smaller, and may take several minutes of attempts for cards with many GB).

Also, you may try specifying fixed VRAM size, via command line, like memtest_vulkan 0 90000000000. This avoids any guesses about which size to test, but will not workaround driver limit, but make more obvious which allocation works fine and which not.

[tonycstech]

Win10 X64 No errors, its just using 20GB max out of 96GB so i cannot tell if memory is good. Using 20GB is like testing 10 chips and not knowing the rest of them are dead.

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On Fri, Jul 31, 2026 at 6:04 AM Vasily Galkin ***@***.***> wrote: *galkinvv* left a comment (GpuZelenograd/memtest_vulkan#86) <#86 (comment)> No specific limit known, unless imposed by the driver. Here 29GB is allocated for 5090: https://www.overclock.net/attachments/1766265953822-png.2743634/ Full 32GB is not allocated on RTX5090, some percent is left to OS to avoid it hangs. Which OS? How exactly it behaves - hang/error message? Rename to memtest-vulkan-verbose and show its output (more detailed). From my experience - for windows a swap file with size similar to VRAM is needed, otherwise driver sometimes forbids huge allocations. So, if on Windows, try making huge swap, it won't be used, but needed. And when huge allocations are forbidden - memtest_vulkan automatically tries to auto-select lower VRAM size. The auto-selection algorithm is bad (linear, each attempt is 0.5GB smaller, and may take several minutes of attempts for cards with many GB). Also, you may try specifying fixed VRAM size, via command line, like memtest_vulkan 0 90000000000. This avoids any guesses about which size to test, but will not workaround driver limit, but make more obvious which allocation works fine and which not. — Reply to this email directly, view it on GitHub <#86?email_source=notifications&email_token=AOUZUBRQSPE2X6W3NCO4CTL5HRVLFA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTKMJUGE3TAOJSGM42M4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2KYZTPN52GK4S7MNWGSY3L#issuecomment-5141709239>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AOUZUBX4FHYSSH3KXQCSMJL5HRVLFAVCNFSNUABFKJSXA33TNF2G64TZHM2TCMBVGAYDSMJTHNEXG43VMU5TKMBSGI4TMOJQGAY2C5QC> . Triage notifications, keep track of coding agent tasks and review pull requests on the go with GitHub Mobile for iOS <https://github.com/notifications/mobile/ios/AOUZUBVAQVFO5WJJGHUVOAD5HRVLFA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTKMJUGE3TAOJSGM42M4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2KUZTPN52GK4S7NFXXG> and Android <https://github.com/notifications/mobile/android/AOUZUBXMI4BQG7T6NZFQMAD5HRVLFA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTKMJUGE3TAOJSGM42M4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2K4ZTPN52GK4S7MFXGI4TPNFSA>. Download it today! You are receiving this because you authored the thread.Message ID: ***@***.***>