LPX 3600 won't run at 3600

[[TW]Fox]

Hi all,

Just built my new system - Ryzen 5600x, 3070FE, Asus B550-E and 4x 8Gb sticks of Corsair LPX 3600.

Everything is fine but obviously as standard the memory runs at PC3200.

I cannot get it to run stable at 3600. If I set DOCP, the machine doesn't POST. If I set memory speed manually to 3600, it does post but with the most ridiculously high timings (ie, CAS 24). If I set memory speed manually to 3600, voltage manually to 1.35 and CAS to 18 as per ratings it runs but crashes before the end of 3dmark.

If I leave it alone at 3200 everything is fine.

What gives? Isn't this memory supposed to run at 3600 CAS 18?

 

[pc-guy]

you need more volts on the CPU memory controller to run 4 sticks.

 

[mickyflinn]

Xmp profile is overclocking so not guaranteed set the timings manually and up the voltage you should be good up to 1.45v.

 

[[TW]Fox]

you need more volts on the CPU memory controller to run 4 sticks.

Interesting - so it's insufficient to just to the ram voltage? What would you suggest I increase it too?

 

[[TW]Fox]

So all memory set manually as per Corsair spec, 1.35v and 1.1v SOC.

No post

 

[pc-guy]

Vddg_iod and Vddg_ccd to 1.05 max and try that. you can yank the ram volts to 1.4V

there are many issues affecting 4 sticks of ram - CPU memory controller, motherboard construction and compatibility and silicon lottery when it comes to actually running those 4 sticks at 3600MHz

also enable gear down mode

 

[[TW]Fox]

I'll give that a try.

Disappointing that Corsair market this as a 4x8gb PC3600 kit if it's so difficult to get it running as such

 

[HoneyBadger]

I'll give that a try.

Disappointing that Corsair market this as a 4x8gb PC3600 kit if it's so difficult to get it running as such

Is it the AMD Ryzen tuned variant?

 

[[TW]Fox]

Doesn't look like it. Says Intel XMP certified on the box.

 

[HoneyBadger]

Doesn't look like it. Says Intel XMP certified on the box.

It’s probably not helping the situation then. If you have recently purchased your existing RAM, consider returning it and getting a Ryzen optimised kit instead.

 

[Ian Evey]

Try 2 sticks and Then the other 2 sticks separately to see if they hold 3600mhz.

 

[fs123]

I'll give that a try.

Disappointing that Corsair market this as a 4x8gb PC3600 kit if it's so difficult to get it running as such

I bought 4x8GB sticks of Corsair Vengeance RGB Pro 3600MHz and had the same problem. They would not work at any speed when all 4 sticks were inserted but would work perfectly fine when only 2 sticks were used. It didn't matter which 2 sticks I used, they always worked as a pair but never as 4. It could be a motherboard incompatibility so probably best to return them.

I didn't want to risk getting the same issue again so just bought a 2x16GB kit instead.

 

[Dave2150]

Hi all,

Just built my new system - Ryzen 5600x, 3070FE, Asus B550-E and 4x 8Gb sticks of Corsair LPX 3600.

Everything is fine but obviously as standard the memory runs at PC3200.

I cannot get it to run stable at 3600. If I set DOCP, the machine doesn't POST. If I set memory speed manually to 3600, it does post but with the most ridiculously high timings (ie, CAS 24). If I set memory speed manually to 3600, voltage manually to 1.35 and CAS to 18 as per ratings it runs but crashes before the end of 3dmark.

If I leave it alone at 3200 everything is fine.

What gives? Isn't this memory supposed to run at 3600 CAS 18?

Return it and get a 32 (2X16GB) kit. I'd suggest the Crucial Ballistix 3600 C16 kit.

 

[[TW]Fox]

I thought there was a clear performance benefit to using all 4 slots?

 

[HoneyBadger]

I thought there was a clear performance benefit to using all 4 slots?

No, the opposite. The more memory channels populated, the harder the bus has to work, the more pressure on the memory controller of the CPU.

 

[[TW]Fox]

I specifically read an article that said having 4 ranks was 10-15% better than 2 in many respects - and most sticks are now single rank so the only way to guarantee quad rank is to buy 4 sticks?

 

[Dempsey22]

I specifically read an article that said having 4 ranks was 10-15% better than 2 in many respects - and most sticks are now single rank so the only way to guarantee quad rank is to buy 4 sticks?

Read this too, there was a performance gain when running the 4 instead of the 2. My plan is to run 4 with my 5600x too.

 

[HoneyBadger]

It entirely depends on the CPU, some CPU’S do benefit from quad channel, for example threadripper and high end Intel processors, basically server ‘style’ boards and CPU’S. Your CPU isn’t this ‘style’, and the facts are you’re experiencing issues using 4 sticks of non-Ryzen tuned memory.

https://en.wikichip.org/wiki/amd/ryzen_5/5600x

Dual channel controller.

 

[[TW]Fox]

I flashed the bios with the latest beta bios.

This time, setting to docp made timing changes too and this time the machine posts at the correct settings - in theory, everything working as it should.

I'll wait for some stability testing to conclude but it's a good start..

 

[Stu]

I specifically read an article that said having 4 ranks was 10-15% better than 2 in many respects - and most sticks are now single rank so the only way to guarantee quad rank is to buy 4 sticks?

As often the case, there is a balance! 4 sticks (rather 4 ranks) will give better performance than 2, provided (1) your PC boots, and (2) all settings remain the same. Obviously condition 1 is very important. Condition 2 is more about the balance... all other things being equal then the extra channels give more performance, but some people find they can overclock 2 rank configs better, overcoming the increased bandwidth of 4 ranks.

Generally speaking though, IMHO, there is typically better stability with 2 dual rank sticks compared to 4 single rank sticks. I think this is a combination of both the mobo and the mem controller on the CPU, with mobo being more significant... others know better than me here though.