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AMD's Ryzen 9 9950X3D2 Dual Edition crams 208MB of cache into a single chip

arstechnica.com

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Re: AMD's Ryzen 9 9950X3D2 Dual Edition crams 208MB of cache into a single chip

#171

Post by WD-42 »

hxorr wrote: post #161
WD-42 wrote: post #116

Earlier quoted context omitted.

I’m running 128gb on a 9550x now with 4x32gb sticks and it’s terrible. It’s unstsable, post time is about 2 minutes (not exaggerating)and I’m stuck at a lower speed. I’m considering just taking 2 of the sticks out and working with 64gb and increasing my swap partition. The nvme drive is fast at least. This is my first time off intel and I have to say I don’t understand the hype.

What ddr5 speed are you running? 6000 is technically an over clock, AMD only guarantees being able to run at something like 4800 or 5200. You may need to bump up voltages slightly for your CPU's IMC (I needed to on my ryzen 8700F to run 6000 stable). Its CPU sample dependant. Also as other commenter pointed out, typically 4 sticks will achieve lower stable clocks

I just yanked two of the sticks out. Who knows, maybe I'll sell them. 64gb is sufficient most of the time anyway, and now I'm running at 4800 instead of 3600 and the boot is much faster. Thanks AMD!

Re: AMD's Ryzen 9 9950X3D2 Dual Edition crams 208MB of cache into a single chip

#172

Post by sspiff »

magicalhippo wrote: post #158
WD-42 wrote: post #134

Earlier quoted context omitted.

It'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.

I'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?

It'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.

Re: AMD's Ryzen 9 9950X3D2 Dual Edition crams 208MB of cache into a single chip

#173

Post by rasz »

senfiaj wrote: post #113

Back in 2004 my PC RAM was 256. My relative's laptop had 128. That's crazy when a modern CPU cache can theoretically host an OS (or even multiple OSes) from early 2000s.

256MB was pretty much bare minimum to run contemporary software on a PC in 2004.

"Feb 2001 128MB DIMM was $59. Aug 2001 256MB module was $49. Feb 2002 256MB $34. April 2003 hit bottom with $39 512MB DIMMs"

Re: AMD's Ryzen 9 9950X3D2 Dual Edition crams 208MB of cache into a single chip

#174

Post by justinclift »

sspiff wrote: post #172
magicalhippo wrote: post #158

Earlier quoted context omitted.

I'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?

It'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.

Wonder 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.

Re: AMD's Ryzen 9 9950X3D2 Dual Edition crams 208MB of cache into a single chip

#175

Post by modeswitch »

Tostino wrote: post #22
modeswitch wrote: post #11

Earlier quoted context omitted.

The 3D V-Cache sits underneath only one of the CCDs. See https://en.wikipedia.org/wiki/Ryzen#Ryzen_9000 .

Did you forget which thread we are on?

Oh heh, I thought they were asking about the X3D. My bad ><.

Re: AMD's Ryzen 9 9950X3D2 Dual Edition crams 208MB of cache into a single chip

#176

Post by sspiff »

justinclift wrote: post #174
sspiff wrote: post #172

Earlier quoted context omitted.

It'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.

Wonder 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.

The controllers which support ECC are usually a lot better and able to handle more channels. They also typically require active cooling.

Re: AMD's Ryzen 9 9950X3D2 Dual Edition crams 208MB of cache into a single chip

#177

Post by magicalhippo »

sspiff wrote: post #172
magicalhippo wrote: post #158

Earlier quoted context omitted.

I'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?

It'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.

Ok, 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.

Re: AMD's Ryzen 9 9950X3D2 Dual Edition crams 208MB of cache into a single chip

#178

Post by justinclift »

sspiff wrote: post #176
justinclift wrote: post #174

Earlier quoted context omitted.

Wonder 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.

The controllers which support ECC are usually a lot better and able to handle more channels. They also typically require active cooling.

Interesting. 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

Expensive though.

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