MP 1,1-5,1 Video card memory anomaly

[majus]

Mac Pro 4,1->5,1.
I bought an NVIDIA Quadro K5000 on eBay to replace the GTX 980 (from MacVidCards, which was not working correctly). I just noticed today that it is showing in SysInfo as 3.5GB memory when it should be 4GB. I am almost positive that it showed correctly when I first got it about a month ago but I could be wrong, and it seems to be working fine.

Does anyone have any idea why this would be?

 

[skizzo]

I've read somewhere in the past some video cards have ECC ram that sort of "reserve" some of the vram for those ECC needs. quick google of the card you listed suggests this could be the reason. refer to last page under "NVIDIA CUDA® PARALLEL PROCESSING ARCHITECTURE" it states "Error-correction codes (ECC) memory"

ECC RAM on GPUs is I believe more common for workstation type GPUs, this feature is not really used for gaming GPUs from what I know

https://www.nvidia.com/docs/IO/140231/NV_DS_QUADRO_K5000_11_05_NV_US_LR.pdf
[doublepost=1566924077][/doublepost]and to comment why it may have showed 4GB originally.....can you turn on/off the ECC function somewhere in NVIDIA control panel? if it allows you to turn that feature on/off that could explain why its reporting 3.5 instead of 4. if that exists try switching it on/off and see if that makes a change

 

[Alex Sanders74]

This was a discovered issue with the GTX970 that resulted in Nvidia getting sued. Not sure if the K5000 fell into the same category....

https://arstechnica.com/tech-policy...0-customers-in-class-action-lawsuit-over-ram/

 

[bsbeamer]

Mac Edition of K5000 is GK104, which is Kepler based. This is same as many GTX 6XX series and GTX 7XX series, including GTX 680 Mac Edition, GTX 775M/780M Mac Edition (mobile). Do not believe the lawsuit impacted this generation of GPUs. The GTX 970 is Maxwell based.

 

[orph]

my GTX 770 4GB has the same 3.5gb +0.5gb vram setup just so few of them no one talks about it.

you can see in GPUz so that may be it.

if you have windows look on that side it can be easier to get info there.

can you post a photo of your GPU or a link to it online (the same model you have if from online)?

 

[majus]

Finally found time to reinstall and test the card, and having ECC enabled was definitely the problem. I remembered turning it on about two weeks ago. After turning it off I now have the 4GB back.

can you post a photo of your GPU or a link to it online (the same model you have if from online)?

Sure. The card I have does not have a serial number barcode sticker on it. Here's a pic from Amazon. The only difference on my card is the removable tab portion shown circled has not been removed.

 

[orph]

the ram reading may also just be a software error, may be worth looking in an app that uses vram and checking how much it see's with ECC on/off like PP/AE etc

ECC is not needed by most people so it's not a big loss

cool wanted to check it was not a funky card, that's a legit one (there's been a lot of fake GPU's but that ones real the fake ones look fake idk why people get them, the fake ones show wrong vram sometimes)

 

[bsbeamer]

Adobe PS and AE might be your best bet for common Mac-based apps to check VRAM while in use. Will mention, if you're constantly using CUDA, the reported VRAM will occasionally drop slightly. Believe it's just a reporting error, but never was a big enough deal to actually look into. Do not see that same error with RX580's in Mojave.