Question Is using 4 DIMMS with a 285K a bad Idea ?

[Regev]

I got the Intel 285K CPU and the Gigabyte Z890 Aorus Master motherboard.

I know the IMC on Intel is much better than AMD. Am I likely to face the same problems as AMD owners face when running 4 DIMMs?

I got 4 x 24GB Patriots, 8000MHz, CL36 1.4V. I was going to simply enable Intel 200S boost to overclock the entire system while keeping the warranty (this is why I bought 8000 kits at 1.4v, as this is the maximum the 200s boost allows. The low latency was a sweet bonus).

Your thoughts?

Thanks

 

[Lutfij]

Your thoughts?
What sort of (real world)use case scenario(beyond benchmarking) has you running 96GB's of ram at 8000MHz?

I got 4 x 24GB Patriots, 8000MHz, CL36 1.4V.
You already have the rams in hand, might as well try them out and see if the IMC can hold onto it.

 

[Gururu]

Certainly aiming high. I would be very surprised but let us know how it looks once you try.

 

[Regev]

Your thoughts?
What sort of (real world)use case scenario(beyond benchmarking) has you running 96GB's of ram at 8000MHz?

I got 4 x 24GB Patriots, 8000MHz, CL36 1.4V.
You already have the rams in hand, might as well try them out and see if the IMC can hold onto it.

No use case scenario. I simply want to populate all 4 RAM slots for the looks, and... i'm also curious Worth mentioning, I buy the RAM for half the price it costs in my own country, so the resale value is always there. Also, I may end up passing that computer down after a year or so to a business partner who started training LLMs, so the amount may prove useful to him.

Was just worried that even if it *does* run, it may place too much stress on the IMC. I am using a 420 AIO, perhaps that helps. And the mobo is high-end that supports 9600 or 9800 I think.

Certainly aiming high. I would be very surprised but let us know how it looks once you try.

Seems like that's what I'm going to do
Is a regular MEMTEST enough to verify success?

 

[Misgar]

The spec for the 285K on CPU World is DDR5-6400, so good luck getting 4 DIMMs to run at 8000MT/s.
https://www.cpu-world.com/CPUs/Core_Ultra_9/Intel-Core Ultra 9 285K.html

I'd boot the system at JEDEC default for the RAM (no XMP), install Windows, then enable XMP and work your way gently up towards 8000MT/s, with MemTest86 when you get past 6400MT/s.

By the way, I hope you bought a single kit of 4 matched DIMMs, not two unmatched pairs. If the latter, the kits may contains memory chips from different bins, which could lead to instability at higher speeds.

Try not to get the two kits mixed up when installing. Mark the pairs when they come out of the packet. The differences might be very small, but they may knock 200MT/s off the maximum overclock.

 

[Regev]

The spec for the 285K on CPU World is DDR5-6400, so good luck getting 4 DIMMs to run at 8000MT/s.
https://www.cpu-world.com/CPUs/Core_Ultra_9/Intel-Core Ultra 9 285K.html

I'd boot the system at JEDEC default for the RAM (no XMP), install Windows, then enable XMP and work your way gently up towards 8000MT/s, with MemTest86 when you get past 6400MT/s.

By the way, I hope you bought a single kit of 4 matched DIMMs, not two unmatched pairs. If the latter, the kits may contains memory chips from different bins, which could lead to instability at higher speeds.

Try not to get the two kits mixed up when installing. Mark the pairs when they come out of the packet. The differences might be very small, but they may knock 200MT/s off the maximum overclock.

I was simply going to order a 2 x 24GB kit of 8000MHz 1.4V (hard to find those for a good price), then when I found one, I thought, what the heck - let's get two kits and see if I can run them together. Worst case, I'll install that pair somewhere else. Didnt even know theyre selling a kit of 4!

 

[geofelt]

285K runs dual channel, not quad channel.
It IS a single kit, right, not 4 of the same part numbers??
To run at specs guaranteed, all ram must come from a single matched kit.
A 2 x 48gb kit should have cost you half of what you paid.

But... if your purpose was for looks then OK.

 

[Regev]

It's not a single kit. I just ordered two of those (note the sweet pricing!):

https://amzn.to/3GIXPPY

What do you mean it's a dual channel CPU? I thought it had a quad channel IMC.

I was looking for a 8000 kit with tight timings that can run at 1.4V for Intel 200S boost, this seemed like a no brainer. The rest were much more expensive.

 

[geofelt]

It's not a single kit. I just ordered two of those (note the sweet pricing!):

https://amzn.to/3GIXPPY

What do you mean it's a dual channel CPU? I thought it had a quad channel IMC.

I was looking for a 8000 kit with tight timings that can run at 1.4V for Intel 200S boost, this seemed like a no brainer. The rest were much more expensive.

Here are the 285K specs:
https://www.intel.com/content/www/u...-36m-cache-up-to-5-70-ghz/specifications.html

Max # of Memory Channels 2

 

[Roland Of Gilead]

As ha been pointed out, you're leaving yourself open to issues, with 2 kits of 2x24gb. Even if the kits are the same batch, they are different silicon.

One of three things will happen:

1. They will work as intended with no issues.
2. They will work, but may have trouble getting to their rated speeds, and could cause instability.
3. They will not work together.

It's a bit of a crap shoot. I'd be looking for a 4x kit, or just a 2x kit with larger capacity.

 

[Regev]

If you had to estimate, what are the odds those two kits are going to reach 8000Mhz at their desginated CL36 and 1.4V together? Is it lower than 50%?

I'll be using a 420 AIO (hoping the IMC stays cool), with direct fans on the RAMS (literally above them).

Also, lets say they *are* working, are you losing performance (say, FPS in games) by using two dual-channels rather than just one?

 

[Roland Of Gilead]

If you had to estimate, what are the odds those two kits are going to reach 8000Mhz at their desginated CL36 and 1.4V together? Is it lower than 50%?

That's really hard to say. Again it comes down to the silicon lottery and how robust the IMC is.

I'll be using a 420 AIO (hoping the IMC stays cool), with direct fans on the RAMS (literally above them).

Temp of the IMC might react badly to high temps, but, it's much more about the IMC itself and how it can handle the voltage and speeds to run faster than default.

Also, lets say they *are* working, are you losing performance (say, FPS in games) by using two dual-channels rather than just one?

If you populate all 4 DIMM slots, you may have to run it at a base Jedec configuration (unknown outcome until you try them). This would be a performance drop over 2 DIMM slots populated running at rated speed. There is a small caveat there. Intel IMC's don't necessarily react badly to single channel or dual channel. However, AMD CPUs are very sensitive to single/dual channel configs. For AMD systems the increase in performance with single channel versus dual is huge. Normally in the range of 20-25% performance increase. For Intel, it's less than 25%. Prob in and around 10% performance increase from single channel to dual channel.

 

[geofelt]

Odds are low. Wild guess, say 5%.
Getting all 4 to work and pass memtest will likely require speeds closer to stock and higher timings.
To the extent that games depend on ram speeds, that is not good.
But, you are likely not to notice because other factors come into play.

Since you already have them, try it.
Try a 2 stick configuration and check performance.
Then you will have to decide on the aesthetic value.
To me, "pretty is as pretty does"

 

[Regev]

If all 4 sticks don't run at 8000, I'm not going to keep all 4. I'll keep you posted how the IMC handled it.

 

[Roland Of Gilead]

If all 4 sticks don't run at 8000, I'm not going to keep all 4. I'll keep you posted how the IMC handled it.

Good stuff. Let us know how you get on.

 

[Misgar]

If all 4 sticks don't run at 8000, I'm not going to keep all

What will you do if 2 DIMMs don't pass MemTest86 at 8000MT/s, e.g if you can only achieve 7600MT/s? Slow RAM is better than no RAM.

What do you mean it's a dual channel CPU? I thought it had a quad channel IMC.

I've got some old quad channel Xeon server boards with 8 DIMM slots fully populated. You need to differentiate between number of slots and number of IMC channels.

 

[Regev]

What will you do if 2 DIMMs don't pass MemTest86 at 8000MT/s, e.g if you can only achieve 7600MT/s? Slow RAM is better than no RAM.


I've got some old quad channel Xeon server boards with 8 DIMM slots fully populated. You need to differentiate between number of slots and number of IMC channels.

Is that a possibility? xD I trusted Patriot checked them before advertising them at 8000. And I mean, here's a $600 motherboard with the strongest 420 AIO out there, and fans directly above the ram.What could go wrong? A bad lottery with the IMC?

As for the quad controller, this is what confused me -

View: https://www.youtube.com/watch?v=exBDGLt_jYM

 

[Gururu]

Seems like that's what I'm going to do
Is a regular MEMTEST enough to verify success?

IMO time is the best tester. I wouldn't stress test it all unless you are doing life and death stuff. If it runs and you can't detect any issues with anything you do then it's a win. Just make sure the system hasn't dialed anything back to get make it bootable.

 

[geofelt]

One full pass with memtest with NO errors and the ram is ok.

Normal operation will not uncover peculiar situations that you might eventually encounter.