[SOLVED] i5 8400 Z370 with 4000mhz RAM?

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Josef_

Josef_

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I recently bought G.Skill Ripjaws V F4-4000C18D-16GVK (2x8gb) memory in anticipation of a CPU/mobo upgrade a while from now. The replaced memory sticks are 2400/2666 respectively.

It says my CPU (i5 8400, Z370P D3 mobo) only supports a maximum of 2666mhz memory, so 4000mhz seems overkill and useless.

However, my BIOS claims (when XMP profile is activated) the memory runs at 4000 mhz. CPU-Z also shows this number.
  • Does the memory effectively run at 2666mhz or is it capped somehow even though it shows up as running at 4000mhz?
  • If indeed it is (effectively) capped at 2666mhz, would it make sense to add the one 2666mhz stick or does this mess up the dual channel performance boost, since I'd have 3 sticks?
  • I reckon adding both old memory sticks to make 32gb would be a bad idea since all sticks would run at 2400 and there's no difference in gaming performance 16gb vs 32gb, afaik.
I've seen plenty of videos that show a sometimes significant improvement in gaming performance when using higher frequency RAM, but only in scenarios where the CPU is the bottleneck.

I was thinking of upgrading my CPU to an i7 10700k i7 9700k or i9 9900kf to supplement my RTX2060 Super OC 8gb.

Thanks for your time!
 
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Josef_ said:
@nofanneeded Yeah it's more future proof for sure, although real world benchmarks show very little gains in gaming with my gpu. Most games don't use HT and I don't use my pc for anything else but gaming so those extra threads are somewhat useless.

But who knows what future games support.. I'm gonna think about it, the i9 is only slightly more expensive. Ugh, first word problems lol.
Click to expand...

New consoles PS5 and Xbox series X have 8 cores 16 threads ... you will see the difference very soon .

and Just get the i9 it will work ! just it wont overclock good , thats it , at stock? even the 9900KS will work (which is overclocked 9900K)


It is tested by the maker to work at stock .
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Josef_

Josef_

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Task manager says 4120mhz, which makes sense since I slightly OC'd the BCLK from 100 to 103 so my cpu runs at 4.0ghz instead of 3.8ghz (i5 8400, can't be OC'd).

What I wonder is would performance with 2666mhz memory be exactly the same as my current 4120mhz since my cpu can't handle/make use of the extra mhz, supposedly?
 
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Josef_

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sizzling said:
The maximum rated RAM speed of the cpu is irrelevant, even the overclockable 8700k has a supposed 2666mhz. The benchmarks show you can go over these and will see benefits, how much benefit depends.
Click to expand...

I see, so it's actually running at 4.1k ghz. That's awesome. Not sure how much difference it makes but at least it's future proof. Thinking of buying a Noctua NH D15 and an i9 9900kf so I can keep my current mobo.

Since you seem very well versed; would it be a worthy upgrade? Some people have pointed out the i7 9700k is a better option since it has comparable performance and is cheaper, leaving more room to invest in a proper cooler (and get higher OC's), but future games might actually start using those extra threads.

Cheers!
 
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sizzling

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Josef_ said:
I see, so it's actually running at 4.1k ghz. That's awesome. Not sure how much difference it makes but at least it's future proof. Thinking of buying a Noctua NH D15 and an i9 9900kf so I can keep my current mobo.

Since you seem very well versed; would it be a worthy upgrade? Some people have pointed out the i7 9700k is a better option since it has comparable performance and is cheaper, leaving more room to invest in a proper cooler (and get higher OC's), but future games might actually start using those extra threads.

Cheers!
Click to expand...

I would not run a 9900k on your motherboard, the VRM’s are too weak and it’s very likely you will have issues. Are you finding the i5 8400 not meeting your needs?
 
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Josef_

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sizzling said:
I would not run a 9900k on your motherboard, the VRM’s are too weak and it’s very likely you will have issues. Are you finding the i5 8400 not meeting your needs?
Click to expand...

I would like to maximize the performance of my current build (and make it as future proof as possible) without breaking the bank.

I have an RTX 2060 Super (+115/+1010), turbo RAM (apparently, lol) and feel like my cpu is the obvious bottleneck when gaming. I play 1080p@144hz and most current gen games get nowhere near a consistent 144fps, or even 60 with specific titles. Think RDR2, Marvel Avengers, AC: Origins, Odyssey, Valhalla. Poor console ports that are particularly CPU-bound. Youtube videos show that the difference is very significant when paired with my gpu.

The jump from i5 8400 to i7 or i9 9xxx just feels.. right somehow. I'm not planning on advanced OC'ing due to lack of experience, so perhaps the i9 9900 non k would be an option if my mobo has issues with a k.

Thanks for your insight btw.
 
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nofanneeded

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Josef_ said:
True, but I think he meant I will run into issues when overclocking or instability issues even @ stock when under heavy load (gaming in my case).
Click to expand...

If it is tested and listed then it will work. at stock will work 100% even with full loads .

Overclocking is not guaranteed yes. but Stock it will work full load.

If you look at the table even the 9900KS with 124W TDP is listed !
 
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Josef_

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Well, I'm going to trust an expert and not gamble with an i9. Anyway, the 9700k has excellent and comparable performance in gaming (not productivity obviously), is cheaper, so I can buy a top tier Noctua cooler.

Thanks all for the input. Never thought 4120mhz RAM was even possible lol.
 
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nofanneeded

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Josef_ said:
Well, I'm going to trust an expert and not gamble with an i9. Anyway, the 9700k has excellent and comparable performance in gaming (not productivity obviously), is cheaper, so I can buy a top tier Noctua cooler.

Thanks all for the input. Never thought 4120mhz RAM was even possible lol.
Click to expand...

What experts ? the Mobo Makers are Guaranteeing it . even the i9 9900KS with 4ghz all cores and 124 watts is listed there .

at stock it will WORK. That list is not SPECS , it is TESTED CPU on the motherboard.
 
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Josef_

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nofanneeded said:
What experts ? the Mobo Makers are Guaranteeing it . even the i9 9900KS with 4ghz all cores and 124 watts is listed there .

at stock it will WORK. That list is not SPECS , it is TESTED CPU on the motherboard.
Click to expand...

Sure, technically it should work, but it would be testing the limits of the mobo. It didn't even support 9xxx cpu's until there was a BIOS update. The thing is, I won't be able to RMA the mobo if anything goes wrong, I don't have the receipt anymore lol. :(
 
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Josef_

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@nofanneeded Yeah it's more future proof for sure, although real world benchmarks show very little gains in gaming with my gpu. Most games don't use HT and I don't use my pc for anything else but gaming so those extra threads are somewhat useless.

But who knows what future games support.. I'm gonna think about it, the i9 is only slightly more expensive. Ugh, first word problems lol.
 
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nofanneeded

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Josef_ said:
Sure, technically it should work, but it would be testing the limits of the mobo. It didn't even support 9xxx cpu's until there was a BIOS update. The thing is, I won't be able to RMA the mobo if anything goes wrong, I don't have the receipt anymore lol. :(
Click to expand...

NOTHING will go WRONG. the limits is about overclocking , not about STOCK.

IF they LIST it , it will WORK AT STOCK.

You can Sue them and get Millions of dollar if it does not . no company gambles on this. Just dont overclock it .
 
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nofanneeded

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Josef_ said:
@nofanneeded Yeah it's more future proof for sure, although real world benchmarks show very little gains in gaming with my gpu. Most games don't use HT and I don't use my pc for anything else but gaming so those extra threads are somewhat useless.

But who knows what future games support.. I'm gonna think about it, the i9 is only slightly more expensive. Ugh, first word problems lol.
Click to expand...

New consoles PS5 and Xbox series X have 8 cores 16 threads ... you will see the difference very soon .

and Just get the i9 it will work ! just it wont overclock good , thats it , at stock? even the 9900KS will work (which is overclocked 9900K)


It is tested by the maker to work at stock .
 
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Josef_

Josef_

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I can get a deal on a 9900kF, which is just a k without onboard graphics right?

TDP is 95 (65 for my current cpu), I have a Seasonic S12II 520 bronze 80+ and no peripherals.
 
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