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Intel Core i7 Memory Performance

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Cupboard 26th January 2009, 12:01 Quote
It seems odd that overclocked memory often performs slower, even at the same latency as the non-overclocked memory. Is this because things are out of sync in the controller? Another thing I find interesting is the disproportionate jump in performance on the video encoding with the 1706MHz RAM, in fact that whole test is weird with the slowest (seconds) being faster (MHz) than the ones above it.

I think the Crysis graph is the most telling, no matter how much you try, faster memory might get you one extras fps if you are lucky.

Now that Inter have triple channel memory this is going to be irritating for AMD and people buying/selling memory as AMD specific sets have to be stocked to cater for their dual channel nature. Maybe Socket AM3 will change that.
Anyway, great effort, thanks :)

Dugg btw
http://digg.com/hardware/Intel_Core_i7_Memory_Performance
naokaji 26th January 2009, 12:12 Quote
Cupboard, you can use the ddr3 that is still being sold for c2d / c2q p35/45/x38/x48 with am3.

Nice article, good to see that real applications don't care too much about the ram speed / timings, finally something where you can get away pretty cheap on I7 plattform.
Cupboard 26th January 2009, 12:27 Quote
I know you can use the same memory, but you are unlikely to buy a triple channel kit if you have 2 channels /4 slots to fill
mauvecloud 26th January 2009, 13:08 Quote
Quote:
Also, do you need expensive triple channel memory or will dual or even single channel DDR3 do?
This question is shown in the summary before entering the article, so where are the tests with only one or two of the DIMM slots filled?
Denithor 26th January 2009, 14:41 Quote
Great article, as usual. As mentioned it's nice to see the ultra-expensive memory with tight timings & high speed isn't needed to get good performance out of these systems.

I do wish you had included a table with the settings (BCLK, multis, etc) used for each memory speed. The settings are still new and it's kind of hard to keep up with whether you were just changing multis or also adjusting the base clock when you changed RAM & uncore speeds.

And yes, as mauvecloud said, where are the single/double/triple channel mode comparisons?
n3mo 26th January 2009, 18:59 Quote
It was the same with DDR, actually changing from 133MHz SDR to 400MHz DDR gave around 3-5% more performance in server applications and was completely unnoticeable in games. Memory always had far more throughput than the CPU can saturate so it was never an actual issue unless you use large RAMdrives - and even then it is more of an memory amount rather than speed issue.
Jasio 26th January 2009, 20:50 Quote
Prices for DDR3 are coming down fast... really fast. NCIX now has Aeneon 6GB DDR3-1600 9-9-9-24 ktis for $140... which is a huge drop in price. But it seems OCZ is adopting similar measures. Corsair and Patriot seem to be a tad slow with the DDR3 price adjustements it seems. But overall, good overview ... I'm very happy with my Patriot Xtreme kit.
Bindibadgi 26th January 2009, 21:12 Quote
Quote:
Originally Posted by Denithor
Great article, as usual. As mentioned it's nice to see the ultra-expensive memory with tight timings & high speed isn't needed to get good performance out of these systems.

I do wish you had included a table with the settings (BCLK, multis, etc) used for each memory speed. The settings are still new and it's kind of hard to keep up with whether you were just changing multis or also adjusting the base clock when you changed RAM & uncore speeds.

And yes, as mauvecloud said, where are the single/double/triple channel mode comparisons?

I wanted to do a more in depth explanation but it got to midnight yesterday and I just wanted to sleep :( I may add it in if I get time later this week.
naokaji 26th January 2009, 23:08 Quote
Quote:
Originally Posted by Jasio
Prices for DDR3 are coming down fast... really fast. NCIX now has Aeneon 6GB DDR3-1600 9-9-9-24 ktis for $140... which is a huge drop in price. But it seems OCZ is adopting similar measures. Corsair and Patriot seem to be a tad slow with the DDR3 price adjustements it seems. But overall, good overview ... I'm very happy with my Patriot Xtreme kit.

12GB pr0nz

I've noticed it too, I paid ~230£ for my 6GB kit when it came out, it dropped down to 170£, coudn't resist and ordered another one.
wuyanxu 26th January 2009, 23:21 Quote
when are we going to get 4GB sticks??

from 8GB to 6GB isn't really an upgrade, and consider the price difference i'll be paying if i want 12GB, with the added "bonus" of filling all RAM slots, i7 is really unattractive until 4GB sticks appear.

great article, so conclusion is, as always, go for the relative fast one you can afford, as long as there's a little CPU overclock headroom provided by the RAM, no noticeable difference will be present.
Jasio 27th January 2009, 01:52 Quote
Quote:
Originally Posted by wuyanxu
when are we going to get 4GB sticks??

from 8GB to 6GB isn't really an upgrade, and consider the price difference i'll be paying if i want 12GB, with the added "bonus" of filling all RAM slots, i7 is really unattractive until 4GB sticks appear.

great article, so conclusion is, as always, go for the relative fast one you can afford, as long as there's a little CPU overclock headroom provided by the RAM, no noticeable difference will be present.

Seeing as the Asus P6T series of motherboards has 6 DIMM slots and only supports 12GB of RAM... you'd never need 4GB modules. On the other hand, Gigabyte motherboards support 24GB over 6 DIMM slots. But I don't see myself using 24GB anytime soon, but I wouldn't mind topping off my P6T with 12GB within the next ~12-18 months.
naokaji 27th January 2009, 07:08 Quote
Quote:
Originally Posted by Jasio
Seeing as the Asus P6T series of motherboards has 6 DIMM slots and only supports 12GB of RAM... you'd never need 4GB modules. On the other hand, Gigabyte motherboards support 24GB over 6 DIMM slots. But I don't see myself using 24GB anytime soon, but I wouldn't mind topping off my P6T with 12GB within the next ~12-18 months.

A new P6T will be released, called P6T Deluxe V2, it will support 24GB over 6 Dimms, it will be cheaper due to no sas support, otherwise it will be the same as the regular P6T.

If you look at the performance difference between 1333 8-8-8 and 1600 7-7-7, it becomes clear that you can just buy 12GB cheaper ram rather than 6GB of the more expensive stuff, sure, you wont win any benchmarks, but real apps don't care.

24GB on the other hand is not really viable, 4GB Dimms will cost an arm, leg and kidney when they finally come out, it's more a thing for servers.
Of course, that will all change next year or so when we will push 32nm octo cores beyond 4Ghz and consider 24GB normal.:D
wuyanxu 27th January 2009, 08:47 Quote
Quote:
Originally Posted by naokaji

24GB on the other hand is not really viable, 4GB Dimms will cost an arm, leg and kidney when they finally come out, it's more a thing for servers.
Of course, that will all change next year or so when we will push 32nm octo cores beyond 4Ghz and consider 24GB normal.:D

so 12GB is max for this year?

looks like i won't be upgrading my CPU/mobo/RAM this year. i NEED 12GB, and i don't want to fill all RAM slots, like the mistake i did with 4x1GB garbage.
Bindibadgi 27th January 2009, 09:10 Quote
What do you DO that requires 12GB of memory?
-pattoe- 27th January 2009, 09:16 Quote
There is no way on earth you NEED 12 gig man...
impar 27th January 2009, 09:23 Quote
Greetings!

I would wait for 4GB modules before upgrading to Nehalem family.
Specially considering Lynnfield will have a dual channel RAM plus a PCI-E controller.
wuyanxu 27th January 2009, 10:04 Quote
Quote:
Originally Posted by Bindibadgi
What do you DO that requires 12GB of memory?
RAMdisk, finding the current 1.7GB setting small for my liking. and i often need to run 2 virtual machines at once, one for simulation, other for working on the code. oh, i may want to play Sins of Solar Empire while im at it. that's 1.5G (Vista) + 1.7G (Ramdisk) + 1.5G *2 (2 VM) + nearly 2GB for a large Sins game. already hit the 8GB top here. then what if i need to run VMware XP for Modelsim? (can't get it to work on my Linux install)

so a 12GB would be a likely upgrade path.
naokaji 27th January 2009, 10:38 Quote
Quote:
Originally Posted by Bindibadgi
What do you DO that requires 12GB of memory?

running 5 instances of eq2 at once, one GB each gone, then add the usual background applications and 6 GB is not enough, 8 GB was enough, but it's not a option with Tripple channel, so 12GB is the choice.
bubsterboo 27th January 2009, 11:45 Quote
Quote:
Originally Posted by wuyanxu
when are we going to get 4GB sticks??

from 8GB to 6GB isn't really an upgrade, and consider the price difference i'll be paying if i want 12GB, with the added "bonus" of filling all RAM slots, i7 is really unattractive until 4GB sticks appear.

great article, so conclusion is, as always, go for the relative fast one you can afford, as long as there's a little CPU overclock headroom provided by the RAM, no noticeable difference will be present.

I feel exactly the same way. I always shoot myself for buying small sticks when i want to add more memory. So I'm only going to buy the biggest possible size supported by the motherboard. And I'll want triple channel. So until 4gb sticks appear, and won't cost me over say... 350$ for 3 sticks I won't even consider upgrading.
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