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Comment by springtimesun | Hacker News Reader

I’ll be very curious what you get with DDR4. I also almost went that way. I have an Epyc DDR 5 rig and the best I see is 10 tok/s. Caveat being that’s at Q8 and a 4090 doing pre fill so it could be pushed up.

The surprising thing for me is how much work you will need to cool the banks if you’re near your memory ceiling. My memory starts soft throttling at about 74C (dies may be hotter, that’s the bank temp) and will turn down speed to try to stay below 80.

Happy to send my llama.cpp config settings if you want it.

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I am getting 10t/s on unsloth's Q3kxl with 2x3090s@250w. It's enough for me for now. I will probably upgrade the GPUs down the line. DDR5 would have made the price of the machine double and I just wasn't prepared to pay that much.

Temp wise, no throttling, surprisingly cool.

I was running one of the older llamas (3.1 I think?) at slow-ish (10-20 tok/sec at Q4?) but OK speeds on 12 year old DDR3 ECC Xeon machine

I find 10 to be very usable. It’s not (that) interactive but it chews through tasks. I let Kimi churn away at 4 overnight and it gives good results that are ready for me in the morning.

Typically computers with these larger memory amounts have fans that scream like a banshee trying to move impossible amounts of air over the memory and CPU. Getting something both cool and quite can be a bit difficult.

Yes, I thought when I was starting that 1u and 2u form factors were to save space. Maybe they are, but they also have the advantage of moving air front to back very effectively through and over the components. Though there still must be some need because I see even those boxes have optional manufacturer built memory shrouds to try to force airflow between the DIMMs.

I had some 120x38mm fans from another server box that I pulled out because they were too loud and I didn't need the static pressure they were giving. They went in here. That 13mm (and the extra 1k rpm) moves so much more air.

I built a dual epyc server with 64 cores and 1 TB of DDR4. Draws around 800W or so under load. I used off the shelf liquid cooling. It is audible but not noisy.

The trick is to turn on the cooler's RGB in your 6000€ server to get a free speed boost. I am not liable for sysadmin's heart attack upon reading this.

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