Core i7 860 and 1066Mhz RAM

[AndrewJBeard]

What is the impact of pairing a Core i7 860 on a LGA1156 platform (which supports up to 1333Mhz memory) with 1066Mhz memory (assuming standard timings)? Will the 1066Mhz memory affect the speed of the CPU or other components sat on the motherboard (i.e. are the base clock rates linked)? Or is it purely the memory bandwidth that will be affected? If so, would the real-world performance degradation be noticeable?

 

[Whisper2]

I have an i7 860 mounted on a Gigabyte P55-UD4P with OCZ memory rated at 1600, 8-8-8-24 @1.65v. The BIOS allows me to select 1066, 1333 or 1600 directly with the memory mutiplier. I do not have to adjust any other multipliers. The BIOS uses the SPD setting for 1066 (7-7-7-16 @1.5v). The other SPD ratings are next to useless so the BIOS mysteriously adjusts the timings and voltages to these: 1333 (7-7-7-19 @ 1.57v) and 1600 (8-8-8-20 @1.6+) I do not adjust anything other the the memory multplier. The other multpliers remain unchanged.

Bottom line is that I do not notice any difference with the settings and the system runs fine with all of them. I am sure benchmarking would show some changes but I have not run any. I finally settled on the 1333. I prefer the lower timings and voltage over a little more bandwidth.

 

[Ayah]

Pretty much no impact. As Whisper said, you can set a different ratio and run the memory at it's native timings also.

 

[Ben90]

I think the only thing that would have a noticable real world impact is de/archiving things in winrar, if thats all you do 24/7 then i recommend getting the full 1333 memory (or a triple channel x58 platform), but if your like the other 99.99999999% percent of people in this world there will be no noticable impact

 

[ekoostik]

Whisper2,
Did you make any other BIOS changes? Have you tested your Turbo functionality since changing your RAM settings?

The reason I ask is that I discovered at default settings Gigabyte "takes away" Turbo functionality when you change certain settings, including RAM settings. It's easy to turn back on. I think the only reason they do this is so that when someone starts changing settings they (Gigabyte) follow the safest path of disabling certain things (like Turbo) so the board doesn't accidentally do something the user wasn't expecting and get fried.

A number of board settings for "Auto" mean Enabled if you don't tweak other settings but are translated as Disabled if you do tweak certain other settings. The changes I had to make in the BIOS were on the Advanced CPU Core Features page:
Intel Turbo Boost Tech. - changed from Auto to Enabled
CPU Cores Enabled - left as All
CPU Multi-Threading - left as Enabled
CPU Enhanced Halt (C1E) - changed from Auto to Enabled
C3/C6/C7 State Support - changed from Auto to Enabled
CPU Thermal Monitor - changed from Auto to Enabled
CPU EIST Function - changed from Auto to Enabled
Bi-Directional PROCHOT - changed from Auto to Enabled

When I changed the RAM settings and didn't make the above changes, my i7 860 always ran at x21 or x22 (~2.8-2.93GHz). Once I made the other changes, I got my Turbo back and watched the multiplier ramp up to its max x26 (3.46GHz) with 1 thread under full load. It also idles at x9, a bonus in my book for the increased efficiency and lower heat.

 

[ekoostik]

Will the 1066Mhz memory affect the speed of the CPU or other components sat on the motherboard (i.e. are the base clock rates linked)?

It will not affect the speed of the CPU. They use the same base clock, but even at 1066MHz they will both still run with a bclk of 133. The CPU and RAM have separate multipliers. So while your CPU might run at 133x21=~2.8GHz, your RAM can at the same time run at 133x8=~1066MHz.

If so, would the real-world performance degradation be noticeable?

Although somewhat flawed (for example, front page says the test was run on an i7 860 but testing page says i7 870, and, personally, I don't care mcuh for the way the results are shown) the following article can be of some use on the subject:
http://www.tomshardware.com/reviews/core-i7-870-1156,2482.html

 

[lothar]

Whisper2,
Did you make any other BIOS changes? Have you tested your Turbo functionality since changing your RAM settings?

The reason I ask is that I discovered at default settings Gigabyte "takes away" Turbo functionality when you change certain settings, including RAM settings. It's easy to turn back on. I think the only reason they do this is so that when someone starts changing settings they (Gigabyte) follow the safest path of disabling certain things (like Turbo) so the board doesn't accidentally do something the user wasn't expecting and get fried.

A number of board settings for "Auto" mean Enabled if you don't tweak other settings but are translated as Disabled if you do tweak certain other settings. The changes I had to make in the BIOS were on the Advanced CPU Core Features page:
Intel Turbo Boost Tech. - changed from Auto to Enabled
CPU Cores Enabled - left as All
CPU Multi-Threading - left as Enabled
CPU Enhanced Halt (C1E) - changed from Auto to Enabled
C3/C6/C7 State Support - changed from Auto to Enabled
CPU Thermal Monitor - changed from Auto to Enabled
CPU EIST Function - changed from Auto to Enabled
Bi-Directional PROCHOT - changed from Auto to Enabled

When I changed the RAM settings and didn't make the above changes, my i7 860 always ran at x21 or x22 (~2.8-2.93GHz). Once I made the other changes, I got my Turbo back and watched the multiplier ramp up to its max x26 (3.46GHz) with 1 thread under full load. It also idles at x9, a bonus in my book for the increased efficiency and lower heat.

I think that issue was fixed in a BIOS update a month ago.

 

[ekoostik]

I think that issue was fixed in a BIOS update a month ago.

I'll have to re-test. Hadn't checked since one of the F4 (UD2) betas. In the meantime I guess I can lay off the warnings.

 

[ekoostik]

Andrew,
Meant to ask earlier why you're considering slower RAM? It's not something I've seen a lot so I was curious. I just wanted to make sure that if you're considering slower RAM because you have some you're going to reuse that you were aware of the voltage limitation. The RAM needs to run at <= 1.65V.

 

[AndrewJBeard]

Thanks everyone.

The reason I'm asking is that Dell have a sale on an i7-860 system here in the UK but only offer 1066Mhz RAM with it, despite the fact that they sell1333Mhz parts specifically for that system as an upgrade. (Thus far my attempts to convince the sales rep of this fact have failed).

But if, as you say, the difference between the two speeds will barely be noticeable, maybe I should just simply buy it.

 

[Cattykit]

This:
http://www.tomshardware.com/reviews/core-i7-870-1156,2482.html

 

[Whisper2]

ekoostik,

The only other change I made under the Performance tab was to change the Turbo setting from Auto to Enable. I know the Tubo feature is working correctly because I used Intel's Turbo Gadget for a couple of days (I normally don't care much for gadgets and have them disabled but I wanted to see how the feature works in normal use). This gadget shows a vertical bar graph and numerical frequency and is about 2" x 2". I was surprised how dynamic the feature is. It even kicks in sometimes when loading web pages -- fighting off a deluge of third party cookies, guess.

The gadget can be downloaded here:

http://downloadcenter.intel.com/SearchResult.aspx?lang=eng&keyword=&#37;22turbo+gadget"

 

[ekoostik]

Slick gadget. Thanks for the link. I just used it along side CPU-Z to do some testing. Wish it showed the real time speed, with EIST on my PC often runs idle at 1.2GHz. But I guess the point of the gadget is to show off Turbo mode. Just for fun I'll kick off a single thread in Prime95 to watch the meter jump to 3.46GHz.

 

[ekoostik]

I think that issue was fixed in a BIOS update a month ago.

I finally got around to testing this. I loaded up the latest BIOS (F6 for the GA-P55M-UD2) and tested it by turning on XMP. Same behavior as before. The board increased my memory multiplier to x12, and decided to be safe by "taking away" functionality such as Turbo and EIST.

In fact once I booted up with XMP on, I found that I had a CPU locked at 2.93 GHz. It's easy to "fix" though. As I described earlier, you just have to manually tell the board what you want it to do. On the Advanced CPU Core Features page change:
Intel Turbo Boost Tech. - from Auto to Enabled
CPU Cores Enabled - leave as All
CPU Multi-Threading - leave as Enabled
CPU Enhanced Halt (C1E) - from Auto to Enabled
C3/C6/C7 State Support - from Auto to Enabled
CPU Thermal Monitor - from Auto to Enabled
CPU EIST Function - from Auto to Enabled
Bi-Directional PROCHOT - from Auto to Enabled