Crappy (supposedly) Memory overclocking on 8700k
So basically, trying to overclock this crap Crucial - 32GB memory.
Before you say anything! I know. I know. It is a crap memory. Even though A number of people has really good experience with overclocking this, I shouldn't be too optimistic.
And indeed, I was not. I expect it to top out at 2400, at maybe 16-16-16-34 2N or something, but to my surprise. This memory is currently working flawlessly at 3000 17-17-17-38 1N with 1.35v. It will even boot at 3099 17-17-17-38 1N, but very unstable, crash in OCCT within 10 minutes. It will also work at 2600 15-15-15-36 1N fully stable ( as in 8 hours of Memtest and 8 hours of Google memory test), it will boot at 2666 15-15-15-36 1N, but not fully stable (Crash in OCCT after a few hours).
My First Question is, which one do I pick, if I can only pick these two?
- 2600 15-15-15-36 1N
- 3000 17-17-17-38 1N
It looks like 1 has slightly better latency but 2 has better bandwidth, but the latency different is slight. 59ns vs 61ns. While bandwidth different is between 28GB/s vs 35GB/s
My Second question is, where do I go to push a little more?
Before you say anything! I know, I know. I shouldn't push my luck with such crappy memory, but I would like to know from someone who has more experience in overclocking, based on what I said, what does it look like I should do? I will say the following too.
3000 17-17-17-38 1N is stable, but 3099 is not,
Changing System Agent Voltage (aka VCCSA) 1.25v doesn't seems to matter, 3099 still isn't stable no matter what. Same with VCCIO, I changed that to up to 1.25v makes no different. Memory voltage going up to 1.45v makes no different, what else should I do? Should I touch VTTDDR? OR is there something else missing?
PCPartPicker part list / Price breakdown by merchant
| Type | Item | Price |
|---|---|---|
| CPU | Intel - Core i7-8700K 3.7GHz 6-Core Processor | $350.98 @ Newegg |
| CPU Cooler | NZXT - Kraken X62 Rev 2 98.2 CFM Liquid CPU Cooler | $147.32 @ OutletPC |
| Motherboard | Gigabyte - Z370 AORUS GAMING WIFI (rev. 1.0) ATX LGA1151 Motherboard | $159.99 @ Newegg |
| Memory | Crucial - 32GB (4 x 8GB) DDR4-2133 Memory | $344.99 @ Amazon |
| Storage | Samsung - 960 EVO 500GB M.2-2280 Solid State Drive | $199.99 @ B&H |
| Video Card | MSI - Radeon R9 280X 3GB TWIN FROZR Video Card | - |
| Case | Fractal Design - Define S w/Window ATX Mid Tower Case | $49.99 @ Newegg |
| Power Supply | SeaSonic - S12II 620W 80+ Bronze Certified ATX Power Supply | $34.90 @ Newegg |
| Prices include shipping, taxes, rebates, and discounts | ||
| Total (before mail-in rebates) | $1303.16 | |
| Mail-in rebates | -$15.00 | |
| Total | $1288.16 | |
| Generated by PCPartPicker 2018-03-14 15:49 EDT-0400 |
Any help would be appreciated!
Posted Mar 14, 2018, 7:51 PM UTC
SA/IO voltage can be pushed to roughly 1.2V with negligible gains after that. Vdimm at 1.45V is starting to get aggressive though. I'd pick the 3000 @CL17 and see if you can tighten the timings.
I have tried dropping it to CL16, 16-17-17-38 instantly became unstable. And yes I already tried both SA/IO to 1.25V and see no differences. I am guessing my memory is pretty much sitting right at the edge of stability.
I'm just surprised that I can't get anything more stable at all even after Vdimm over 1.45V.