F3-17000CL11D-8GBXL overclocking

[Haswell OCer]

I have 2 sets of these ram 4x4 16gb 2133 F3-17000CL11D-8GBXL I was wondering since I have a haswell 4670k and a Gigabyte Z87X-UD4H motherboard just how far can these go for overclocking can I get 2400 out of these or even up to 2800 if so what timings can I try and voltage thanks ....

[emissary42]

What clocks you can get out of them, depends on the ICs used. DDR3-2133 CL11 is a specification many different ICs can do. So i would start with DDR3-2400 and 1.65V at either 10-12-12-31 or 11-13-12-31/11-12-11-31.

[Haswell OCer]

So there is no limit for the ram its the chipset memory controller I thought 4670k could handle ram at 2800 if so what timings can I try for lets say for 2600 and 2800 .. I would like to try ....

[emissary42]

No, there are limits for memory as well and with haswell your basically not imc limited with almost anything but some very special kits. I could give you some random timings for 2666 or 2800, but without even knowing if and at what timings/voltage you're kit can do 2400, that would be kinda pointless... If you want to try it anyways, start somewhere around 12-15-15-35 to 11-13-13-31 for the main-timings. Customize subs and increase voltages if needed. Reading a general oc guide for haswell before that, might be a good idea ;-)

[Haswell OCer]

Can my ram run at 1.7 volts or is that dangerous since they are rated at 1.6 volts
.

[emissary42]

A vdimm of 1.7V is still in an ok-range for some ics, but might not be for others. It is also questionable, if that is still safe for daily use with your cpus imc. However there is very little evidence on degraded haswell processors by high dimm voltages yet. So as always with overclocking: "Overclocking may void your warranty and damage your system! Do this at your own risk."

I would start lower in both voltage and frequency and then move on up, step by step.

[Haswell OCer]

I got them stable at 11-12-12-30 2400 at rated 1.6 volt ... I guess they are no crashes when playing Saints Row 4 for the last two hours do you think I should go higher or is 2400 good enough ..

[emissary42]

Just as a backup save these settings to a bios profile / on an usb-stick or write them down. If something goes wrong while overclocking, you can start over from that point.

The timings you ended with at ddr3-2400 can still be two or three different ics. Next step would be ddr3-2600 and then 2666 at say 11-13-12-31 / 11-13-13-31 / 11-14-13-31 / 12-13-13-31 / 12-14-13-31. If even the last one is a no go, then either your subs/voltages need a fix or your memory has hit its wall. The higher the timings needed, the lower the performance improvement will be. Very loose (sub-) timings could even backfire to an extent. So it helps to compare bandwidth, latency and/or overall performance of these settings with your starting point at 2400 11-12-12-30 every once in a while during testing.

If 2666 CL11-13-13 is possible at or below 1.65V, then 2800 CL12-14-14-35 could be doable. Keep an eye on the system voltages however. Some mainboards raise those way above what is actually needed @ AUTO settings.

[Haswell OCer]

I think 2400 is the sweet spot going to 2600 is all I can do with out a crash but when doing a memory benchmark at 2600 11-13-13-35 it gets worse scores than 2400 11-12-12-28 also weird things happen like black squares in my web browser I don't want to kill them also for some reason it seems these ram dont like the 1.65 voltage they run way smoother at 1.6v .. So I guess 2400 is it for these rams and I only paid for 2133 you cant beat that ...