ram Memory Recommendation Needed!

[Cyano_Hibiki]

Hi all,

 

I recently built a new PC, and is looking into upgrade my memory sticks. Here is the current configuration of my new rig:

• CPU: Ryzen 7 5800X
• MoBo: ROG Crosshair VIII Dark Hero
• GPU: AMD 6800XT (ASUS TUF Series)
• RAM: Corsair Dominator Platinum 3200MT/s C16 (16GB x2)

The RAM is taken out from my old rig, which had a Ryzen 2700X and a X470 mobo. I want to repurpose the old rig, which means I need to buy some new memory.

I am not sure if I should buy chearper RAM for my old rig, or buy better ones to replace the Corsair sticks I am currently using in my new rig.

Which route would you suggest I take? And what brand / specific frequency and timing should I use? I appreciate your help!

[ramava]

If you can find some C14s in your budget, it might be a little upgrade. Even if they're still 3200. If you don't have the budget for faster RAM, what you have is just fine too. Or to save a few bucks, maybe just be 2x8GB for the old rig.

[Chris Pratt]

I wouldn't go any lower than 3200MHz for either system. Given that, you should probably just get a new 3600MHz CL16 kit for your 5800X. There's not really a big cost difference, and it's a lot closer to ideal for the platform.

 

Brand doesn't really matter. They all use the same handful of memory manufacturers (Samsung, Micron, SK Hynix). As long as you go with a reputable name brand, you should be fine (Corsair, G.skill, Crucial, Kingston, etc.)

[Cyano_Hibiki]

13 minutes ago, Chris Pratt said:

I wouldn't go any lower than 3200MHz for either system. Given that, you should probably just get a new 3600MHz CL16 kit for your 5800X. There's not really a big cost difference, and it's a lot closer to ideal for the platform.

 

Brand doesn't really matter. They all use the same handful of memory manufacturers (Samsung, Micron, SK Hynix). As long as you go with a reputable name brand, you should be fine (Corsair, G.skill, Crucial, Kingston, etc.)

Thanks Chris!

So would it be pointless to go beyond 3600 for my platform? I've heard that Ryzen CPUs benefit from higher memory clocks, but I'm not sure to which point will the performance gain fail to justify the price increase. For example, I found that a 32GB kit of Crucial Ballistix 3600MHz C16 costs $187.99, while a 4000MHz C19 kit of the same capacity would cost $373.99. The price is almost doubled for an uplift of 400 MHz. But I would suppose the performance does not double in this case. (Not sure how memory performance is quantitatively assessed, though.)

 

Also, I noticed that brands like G.skill have sticks with lower latencies, such as 3600 C14, 3800 C14, etc. Their prices are roughly $100 higher than their higher latency (C16) counterparts. Do you think this reduced latency is worth the extra money?

[Chris Pratt]

The "fastest" RAM you should get for Ryzen is tied to how high the FCLK can go. For Zen 3, it runs 1900MHz stock, so technically 3800MHz RAM would be the best, but that's not a very commonly available clockspeed. In some cases, the FLCK can be OCed as high as 2000MHz, which if you can get yours that high, then 4000MHz may be worthwhile, but if you can't get the FCLK to 2000MHz, that, and definitely anything with higher clockspeeds, will actually be slower, since the FCLK will go 2:1 instead. For example, if you paired it with something like 4400MHz, it would effectively be the same performance as like 2133MHz RAM, because you'd never be able get the FCLK up to 2200MHz.

 

3600MHz is a good compromise speed. Zen 2's stock FCLK is actually 1800MHz, so it just perfect for that. While you can do a little better on Zen 3, 3600MHz is close enough, more easily available, and relatively cheap, compared to other options.

 

Clockspeed matters more than timings, i.e. 3600MHz CL16, is better than 3200MHz CL14, but given the same clockspeed, lower timings are better. However, very tight timings like 3600MHz CL14, while technically "better", are disproportionately expensive, and not really ever worth the cost. For perspective, CAS latency should basically be 1/2000 of the rated clockspeed, i.e. 3600MHz CL18. 3600MHz CL16 would already be tight timings. 3600MHz CL14 would be as tight as really possible.

[Cyano_Hibiki]

15 minutes ago, Chris Pratt said:

The "fastest" RAM you should get for Ryzen is tied to how high the FCLK can go. For Zen 3, it runs 1900MHz stock, so technically 3800MHz RAM would be the best, but that's not a very commonly available clockspeed. In some cases, the FLCK can be OCed as high as 2000MHz, which if you can get yours that high, then 4000MHz may be worthwhile, but if you can't get the FCLK to 2000MHz, that, and definitely anything with higher clockspeeds, will actually be slower, since the FCLK will go 2:1 instead. For example, if you paired it with something like 4400MHz, it would effectively be the same performance as like 2133MHz RAM, because you'd never be able get the FCLK up to 2200MHz.

 

3600MHz is a good compromise speed. Zen 2's stock FCLK is actually 1800MHz, so it just perfect for that. While you can do a little better on Zen 3, 3600MHz is close enough, more easily available, and relatively cheap, compared to other options.

 

Clockspeed matters more than timings, i.e. 3600MHz CL16, is better than 3200MHz CL14, but given the same clockspeed, lower timings are better. However, very tight timings like 3600MHz CL14, while technically "better", are disproportionately expensive, and not really ever worth the cost. For perspective, CAS latency should basically be 1/2000 of the rated clockspeed, i.e. 3600MHz CL18. 3600MHz CL16 would already be tight timings. 3600MHz CL14 would be as tight as really possible.

Thank you so much for your patience to walk me through all these details. This is very informative!