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A Question about QPI

AWBbox

AWBbox

AWBbox

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Hi guys, I am struggling to understand the basics of QPI. Can any of you help me out please?

I wanted to know if the 6.4GTs of a core i7 965 made an real performance improvements over the 4.8GTs of a core i7 920. Sorry if I am overwhelming you with my ignorance but if anyone could explain how this works and what difference there really is I would be grateful.

Thank you!
 
The overwhelming consensus is that a 920 is a million times better bang for buck than a 940 or a 965, as they overclock to similar levels.

The 950 and 975 might be interesting though.
 
AWBbox said:
Hi guys, I am struggling to understand the basics of QPI. Can any of you help me out please?

I wanted to know if the 6.4GTs of a core i7 965 made an real performance improvements over the 4.8GTs of a core i7 920. Sorry if I am overwhelming you with my ignorance but if anyone could explain how this works and what difference there really is I would be grateful.

Thank you!
Click to expand...

It's completely irrelevent as you can put the 920 to 6.4GT with 2 or 3 simple button presses on your keyboard in the bios with no drawback.
 
Ah that's cool, I considered that it might be something that was locked to the CPU, meaning that you had to get a 965 if you wanted the extra edge. I'm glad the 920 clocks as well as the other two. But I wouldn't actually mind budgeting for a 940 if given the chance, would there actually be any benefit at all in doing this then?
 
Get the 920 as they all clock about the same anyway.

If you get a good one you should reach 3.8Ghz easy provided you have good cooling.
 
AWBbox said:
Hi guys, I am struggling to understand the basics of QPI. Can any of you help me out please?

I wanted to know if the 6.4GTs of a core i7 965 made an real performance improvements over the 4.8GTs of a core i7 920. Sorry if I am overwhelming you with my ignorance but if anyone could explain how this works and what difference there really is I would be grateful.

Thank you!
Click to expand...

My 920 is running with a 7.2GTs. :D

Basically as you increase the BCLK (FSB) the QPI gets overclocked too.
 
mmj_uk said:
My 920 is running with a 7.2GTs. :D

Basically as you increase the BCLK (FSB) the QPI gets overclocked too.
Click to expand...

Oh man, I am really am out of touch. It's like learning this stuff all over again :confused:

I don't plan on upgrading my system as far as the mobo/cpu is concerned at least for a good few months. But I guess it's only really going to make sense when I have the BIOS screen in front of me and I can have a mess about.
 
AWBbox said:
Oh man, I am really am out of touch. It's like learning this stuff all over again :confused:
Click to expand...

It's similar to the old systems with multipliers etc but there are just newer technologies involved.

The QPI clock derives from the BCLK (Base Clock) which at stock is 133Mhz and there are 3 different multipliers which are x18, x20 & x24.

The 920/940 are both locked on the x18 multiplier AFAIK (which is actually the best for overclocking anyway) whereas the 975 can select all of them.

So for example stock i7 920 is 133x18=2400 which multiplied by 2 is 4800GTs, if you overclock the BCLK to 166Mhz you get 6000GTs.
 
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Thanks for explaining that, it doesn't sound quite as scary now lol. I was getting worried that technology had overtaken me by a long way but what you say kind of makes sense. I get the BCLK bit but I don't know if I fully understand where the multiplication of two comes into it for determining the QPI speed though.
 
AWBbox said:
Thanks for explaining that, it doesn't sound quite as scary now lol. I was getting worried that technology had overtaken me by a long way but what you say kind of makes sense. I get the BCLK bit but I don't know if I fully understand where the multiplication of two comes into it for determining the QPI speed though.
Click to expand...

It's just the way it is, 2400MHz = 4800GTs, 3200MHz = 6400GTs.

I can't really expand on that as I've not really looked into how it works, I think 2400MHz is the speed of the QPI link and 4800GTs is the bandwidth it offers. :p
 
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mmj_uk said:
The 920/940 are both locked on the x18 multiplier AFAIK (which is actually the best for overclocking anyway) whereas the 975 can select all of them.
Click to expand...

No actually its 20x unless turbo is enabled an its 21. There have been many problems with the 20 multiplier and 19 is known to be a good one. Not necessarily scientific prrof though.
 
engstrom0304 said:
No actually its 20x unless turbo is enabled an its 21. There have been many problems with the 20 multiplier and 19 is known to be a good one. Not necessarily scientific prrof though.
Click to expand...

Yeah mate but I was talking about the multiplier for the QPI bus, not the CPU's normal clock multiplier.
 
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