4 ms·
Your machine takes 30 minutes to boot because of the RAM? Or it takes 30 minutes to load a model?
by secondcoming 6mo ago
Your machine takes 30 minutes to boot because of the RAM? Or it takes 30 minutes to load a model?
- WD-42 6mo agoIt's the RAM. It needs to "trained" which takes some time but for for some reason these boards seem to randomly forget their training, requiring it to happen again.
- jazzyjackson 6mo agohuh, its been a decade since i built a PC, whats changed?
- WD-42 6mo agoMy guess is bigger numbers, higher voltages, tighter timings.
- mort96 6mo agoDDR5 is much, much more fickle than DDR4 and earlier standards. I think it's primarily due to pushing clock speeds (6000 MT/s would be insanely fast for DDR4, but kinda slow for DDR5). Memory training has always been a thing: during boot, your PC runs tests to work out what slight changes between signals and stuff it needs to adapt to the specific requirements of your particular hardware. With DDR4 and earlier, that was really fast because the timings were so relatively loose. With DDR5, it can be really slow because the timings are so tight. That's my best understanding of it at least.
- roboror 6mo agoIt's an AMD thing
- magicalhippo 6mo agoI've never had memory training be forgotten with my AM4 nor LPDDR5-based laptops and NUCs. Is this a new thing with AM5 or something? Or just a certain brand of BIOSes?
- sspiff 6mo agoIt's a common issue on consumer boards with DDR5 and more than two DIMMs installed. Doesn’t affect soldered memory or lower speed memory (like DDR4). Many memory controllers fail to achieve good speeds and timings at all on 4 DDR5 DIMMs, and fall back to running DDR5 at 3600MHz instead.
- justinclift 6mo agoWonder if DDR5 ECC ram has the same problem? I'm meaning the real ECC stuff, not the "on chip only ECC" that all DDR5 has.
- sspiff 6mo agoThe controllers which support ECC are usually a lot better and able to handle more channels. They also typically require active cooling.
- justinclift 6mo agoInteresting. Didn't know about the active cooling requirement. That being said, it's not hard to get a hold of a reasonably modern DDR5 EPYC board. Something like this: https://www.phoronix.com/review/gigabyte-mz33-ar1 https://www.phoronix.com/review/gigabyte-mz33-ar1 Expensive though.
- magicalhippo 6mo agoOk, so user selects too-high speed, controller tries for ages and fails, but doesn't save since it's overridden by user in BIOS? I distinctly recall thinking my LPDDR5 NUCs were broken since they seemingly didn't boot the first time, until I recalled the training stuff. Took up to 15 minute on one of them. But neither has had any issues since, hence my question.