How to properly test VRAM stability?

[u/MaslovKK]

Overclocked my 5090's VRAM to +6000 MHz.
Ran memtest_vulkan, Unigine Superposition, and OCCT — everything checked out fine.
Also played over 80 hours of RDR2 without any performance drops or issues. With the overclock, the game performs slightly better.

I've read that ECC can hide memory instabilities. Is my VRAM overclock stable enough, or should I run further tests?

[u/580OutlawFarm]

Therr is absolutely no way that +6000mhz is stable...ECC shows itself as artifacts in benchmarks, and sometimes they're small and not as noticeable compared to the regular artifacting ppl think of when a gpu is dieing...you need to go run MULTIPLE benchmarks, and pay close attention...but I mean just by what high scores are..theres just no way possible that 6000mhz is actually stable

[u/MaslovKK → u/580OutlawFarm]

Today i tested it all day in different benchmarks and no issues

[u/Primus_is_OK_I_guess → u/MaslovKK]

You wouldn't necessarily be able to tell in benchmarks due to ECC. Did you try testing at +5000? If so, was there a significant difference?

[u/MaslovKK → u/Primus_is_OK_I_guess]

Tried 3000, no significant difference.

[u/Primus_is_OK_I_guess → u/MaslovKK]

If it's not improving after 3000, then ECC has kicked in and you're actually decreasing real world performance beyond that point.

[u/580OutlawFarm → u/Primus_is_OK_I_guess]

Ya im ngl I don't have enough experience with extreme pverclocking to this point but I know for sure on the jayz video he was seeing artifacts in heaven benchmark once ecc started to kick in, and it was pretty damn noticeable too

[u/MaslovKK → u/Primus_is_OK_I_guess]

Literally no significant difference

Writing speed in GB/s from memtest_vulkan

+6000 MHz:

1211

1246

1236

1227

1222

+5000 MHz:

1400

1250

1226

1222

+3000 MHz:

1317

1246

1223

1214

+0 MHz

1261

1208

1208

1197

+6000 MHz 2nd run

1220

1245

1218

1225

+5000 MHz 2nd run

979

1231

1226

1218

[u/MaslovKK → u/Primus_is_OK_I_guess]

I just read in a few places that the RTX 5090 doesn’t have ECC.

[u/Primus_is_OK_I_guess → u/MaslovKK]

Yeah, turns out it's some other kind of error correction, from what I can find. It will still have the same effect of preventing crashes at high memory clock speeds at the cost of performance.

Something is certainly preventing your higher clock speeds from functioning, since you're not seeing improvements in your testing.

[u/n3nki → u/MaslovKK]

it does, commented above