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Use your Nvidia GPU's VRAM as swap space on Linux

79 points by tanelpoder 2 hours ago | 22 comments

> Built for laptops with soldered memory and no upgrade path. If you have an RTX card sitting there with 8GB of VRAM and you're getting swapped to SSD, this puts that VRAM to work.

Well, that does at least answer my immediate question about why I would ever swap from expensive RAM to really expensive RAM:) Feels niche, but when you want it it's a good idea.

Wowfunhappy 5 minutes ago

Another possible reason that occurred to me: what if you have VRAM but you're not using it all the time? For example, let's say you bought a GPU because you like to play video games. When you're not actively gaming, you probably don't need 16 GB of VRAM just to render the desktop. Might as well use it for something else, right?

xfalcox 59 minutes ago

Given my dev machine has 32GB of RAM and 32GB of VRAM that sits mostly idle when I'm not running AI models, this is not that bad of an idea.

RachelF 19 minutes ago

Nice idea, but something has gone very wrong here:

>Sequential throughput: ~1.3 GB/s

[on a RTX 3070 Laptop]

This RTX 3070 chip is on PCIe 4.0 x16 which should give 64GB/s. The 8GB of GDDR6 is 448GB/s.

Swapping to an NVMe drive would be twice as fast, but with higher latency.

dragontamer 40 minutes ago

Remember how 16GBs used to be an enterprise level database mainframe?

Well, GPUs also have stupid amounts of compute on them. I have to imagine that there is some kind of database format that's useful with GPU compute attached.

Since the data is already in VRAM, the GPU can sort, join, or otherwise manipulate data as needed.

einichi 8 minutes ago

oh god please don't create more demand for GPUs

Nate75Sanders 16 minutes ago

Possibly LSM compaction.

usxr1515 3 minutes ago

Nice

willis936 31 minutes ago

I'm more interested in the opposite. Nvidia linux drivers crash when you try to address more VRAM than you have. It'd be nice if they didn't.

SV_BubbleTime 21 minutes ago

They already do that on windows and it kinda sucks. If you are targeting something like LMStudio or ComfyUI, both of those have superior methods to do exactly this.

LouisvilleGeek 17 minutes ago

Finally a use for the expensive ram when it's not needed in workloads!

Now if it could be dynamically used and vacated on other GPU workloads?

UnfitFootprint 16 minutes ago

No software benchmarks? BAR for RAM is cool but I want to see how much it _actually_ beats pcie nvme

hardwaresofton 38 minutes ago

You want to waste VRAM, in this economy?

jcmfernandes 2 hours ago

Q: Why? A: Why not?

effnorwood 22 minutes ago

use your car for an anchor on a big boat!

SV_BubbleTime 20 minutes ago

I mean, if you aren’t using the car while using the boat and it won’t really damage the car… yes?

bobsmooth 23 minutes ago

RAM disks have always fascinated me. In a different timeline every PC has a 100gb of RAM and 50TB HDDs are the norm.

pixl97 3 minutes ago

Back when HDDs were all there was ramdisks were interesting, but SSDs pretty much killed most of that as they have massively increased IOPS over disks.

Hard drives that huge scare me as it would take days to backup all the data off them.

simonask 2 hours ago

I mean, cool, but I’d rather not?

margalabargala 57 minutes ago

So don't. Not everything is for you.

gchamonlive 57 minutes ago

Wouldn't it be faster to swap to vram if you are sitting there with 8gigs of it unused than swapping to ssd and burning its write cycles, assuming you absolutely need swap

dspillett 2 hours ago

So, erm, don't?

Sohcahtoa82 2 hours ago

[dead]