eva2000

This is an intro guide based on my first i7 920 and DFI UT X58-T3EH8 setup I've had since Dec 24th but from my brief experience (with i7 920), there's only a few things you need to know:

1. VDIMM has to be within 0.5v of Uncore voltage (refered to on some boards as QPI/DRAM (Asus) or QPI VTT (Gigabyte) volts or CPU VTT (DFI)) for CPU to be safe above >1.65v DRAM memory voltages. Max vdimm most folks recommend for benching is between 1.8-2.0v for Core i7, some folks go to 2.1v. But more isn't necessarily better as it depends on memory ics and cpu mem controller as well. 24/7 you don't really need more than 1.5-1.66v to get enough memory bandwidth for everyday tasks in triple channel.
2. CPU VTT max 1.35-1.375v spec'd some have benched 1.55v so gives VDIMM a 1.875-2.05v range
3. UNCORE (CPUZ NB frequency) needs to optimally be twice that of MEM frequency
4. SOMETIMES for stability, having VCORE within 0.02-0.03v of CPU VTT might stabilise things
5. Yes, theoretical QPI frequency limit is around 4000Mhz but it's too early to say if we can surpass that, some boards and cpu combinations possible could in future.

Bios screens to illustrate here







DFI UT X58-T3EH8 bios automatically scales UNCORE frequency in bios by a ratio of 2:1 as you increase your DRAM memory frequency in bios.

For example, set DRAM memory frequency at DDR3-1067Mhz and bios automatically moves UNCORE frequency to DDR3-2133Mhz. You can move the DRAM frequency down again and it will keep UNCORE frequency as previously set if you want to try UNCORE frequency greater than 2:1 ratio t DRAM memory frequency. Example bios screen shot.

Download Felix's CPU Tweaker 1.3 beta 3 from Memset thread and you can see your DDRAM, QPI and Uncore (NB) frequencies.



Also, check out NehalemCalc http://i4memory.com/wp/article/539 and Gogar's online Core i7 optimiser tool http://i4memory.com/wp/article/533 both allow you to calculate the memory, cpu bclock, qpi and uncore frequency needed for cpu mhz combinations.





It's too early for a detailed Core i7 overclocking guide until I have more time to analyse everything, so for now this will have to do.

Please feel free to share you insights and learned knowledge with your own i7/x58 systems in this thread so we can all better understand this new platform




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eva2000

Continued...

I still follow the same process i outlined at http://i4memory.com/f55/announcement...y-eva2000.html with every new system including i7/x58. Isolate and test each part of the system i.e. start with memory and memtest86+ then cpu then the rest.

Particularly:

1. Find the limits of your memory before you find limits of your cpu/bclk.
2. Find out what your memory can do on each mem multiplier/cpu multi combination.
3. Find out what voltages your memory likes and what's the optimal voltage difference between vdimm and uncore (cpu vtt) for your particular ram/setup
4. Find out whether the ram likes pwm switch frequencies of reduce 15% or nominal.
5. Find out which of your modules likes which dimm slot 2 or 4 or 6.
6. Find out what auto subtimings translate to in cpu tweaker or memset at each mem frequency/timing combination.

Basically get to know how your ram behaves on the motherboard with your particular i7 cpu before looking into the cpu side. Sure, there's a wide variance between i7 cpu memory controllers but I'm wondering how much of this variance is due to differences in how particular cpu memory controller interacts with different types of memory modules - down to their PCB/trace design ? Or just bios updates

i.e. my Samsung HCF0 based G.Skill PC3-12800HZ didn't do too well with 12/18 and 12/31 bios and that effected cpu stability and what voltages I needed to use. Come 1/06 beta and 1/23 pre beta, HCF0 modules now shine and keep up with Corsair DDR3-2133 Dominator HCF0 and cpu clocking much easier.

Trust me when I say figuring out ram side will make overclocking the cpu much easier

eva2000

Guess not all folks have the basics or under Core i7 cpus, so even more basic explanation might be need. I'd start with reading this bit out dated but useful nonetheless thread at http://www.xtremesystems.org/forums/...d.php?t=205688

So when raising bclk to overclock cpu, you're effectively raising cpu core mhz, qpi frequency, uncore frequency and memory frequency. As you raise those 4 components you need the right amount of

1. vcore for cpu
2. cpu vtt (uncore) for qpi frequency and bclk
3. vdimm for uncore frequency and memory frequency.

Latest version of CPU Tweaker which is read only application for i7 will illustrate the effects of rising bclk from 133 to 214 bclk and how the CPU, QPI, Uncore and Memory frequencies change. Update: CPU Tweaker v1.1 has allowed subtiming changes for X58 boards from Gigabyte, EVGA and now with latest DFI 4/28 bios for UT X58.

CPU Core = 19 x 212bclk = 4028Mhz
Uncore = 22 x 212bclk = 4664Mhz
QPI = 18 x 212bclk = 3816Mhz
RAM = 4x 212bclk = 848Mhz (bios will be 8x 212bclk for DDR3-1696Mhz)

eva2000

It can be a fine balance so far come across 4 types of core i7 cpus from my rounds on forums and my own experience

Type 1 - core i7 cpus that need high to very high cpu vtt to overclock for memory and bclk.

Type 2 - core i7 cpus that like low-medium low cpu vtt to overclock for memory and bclk and scale with cpu vtt and memory voltage

Type 3 - core i7 cpus that only like low-medium low cpu vtt to overclock for memory and bclk BUT DO NOT scale for either cpu vtt and memory voltage or both

Type 4 - core i7 cpus that like cpu vtt close to vcore so you may find the cpu needs high vcore for lower clocks due to cpu vtt requirement for those clocks.

low cpu vtt = 1.3-1.35v
medium cpu vtt = 1.35-1.5v
high cpu vtt = 1.5-1.55v
very high cpu vtt = >1.55-1.65v

lazy

i7 seems so much more confusing then I thought it will be. Reminds me of my opty days..

eva2000

Actually 3rd post above, once you understand that along with 1st posts guidelines it really is alot simplier than previous platforms

HDCHOPPER

AAHHH Ya I will wear out this page george ! thanks for the effort and your time

eva2000

hehe... hope it's of some use for you. Not as polished as other guides, but there really isn't that much to say once you realise there's only a few settings you touch to clock i7/x58