Intel's Core i7 870 & i5 750, Lynnfield: Harder, Better, Faster Stronger
by Anand Lal Shimpi on September 8, 2009 12:00 AM EST- Posted in
- CPUs
Discovery: Two Channels Aren't Worse Than Three
Intel told me something interesting when I was out in LA earlier this summer: it takes at least 3 cores to fully saturate Lynnfield's dual-channel DDR3-1333 memory bus. That's three cores all working on memory bandwidth intensive threads at the same time. That's a pretty stiff requirement. In the vast, vast majority of situations Lynnfield's dual channel DDR3 memory controller won't hurt it.
Move up to 6 or 8 core designs and a third memory channel is necessary, and that's why we'll see those processors debut exclusively on LGA-1366 platforms. In fact, X58 motherboards will only need a BIOS update to work with the 6-core 32nm Gulftown processor next year. P55 looks like it'll be limited to four cores and below.
Because of this, Lynnfield's memory bandwidth and latency cores are actually quite similar to Bloomfield. I used Everest to look at memory bandwidth and latency between a Core i7 975 and Core i7 870 (Lynnfield):
Lynnfield's memory controller is good, easily as good as what's in Bloomfield if not slightly better.
Both processors turbo'd up to 3.46GHz, indicating that Everest's memory test uses no more than two threads. The 975 ran DDR3-1066 memory (the highest it officially supports), while the 870 used DDR3-1333. The faster memory gave the 870 the advantage. Since we're not taxing all four cores, Lynnfield is at no disadvantage from a bandwidth perspective. Surprisingly enough, even SiSoft Sandra (which does use four cores for its memory bandwidth test) shows Lynnfield's dual-channel DDR3-1333 memory controller as equal to Bloomfield's triple-channel DDR3-1066 interface.
| SiSoft Sandra 2009.SP4 | Intel Core i7 975 | Intel Core i7 870 |
| Aggregate Memory Bandwidth | 17.8 GB/s | 17.3 GB/s |
Long story short? Lynnfield won't be memory bandwidth limited with DDR3-1333 for the overwhelming majority of usage cases.
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goinginstyle - Tuesday, September 8, 2009 - link
Really? SuperPi, WPrime, Everest, 3Dmarks and LN2 overclocking defines a better review? How does any of that correlate into real world applications and what 99% of people use their computers for on a daily basis. I counted a lot more than three tests in the AT review, go spam elsewhere.C'DaleRider - Tuesday, September 8, 2009 - link
Really. All I play is SuperPi, Everest and 3DMarks....oh, and Furmark and OCCT.Who would ever use their computer to encode video, run Excel spreadsheets, play games like Far Cry or Crysis or Left For Dead, or actually use any other real world application?
Don't you know? Real elite computer users just bench synthetic crap, over and over, for hours and hours, and scoff at anyone who dares do anything productive with their computer.
/sarcasm
geok1ng - Tuesday, September 8, 2009 - link
I am not pleased by the news; i5 needs more juice for overcloking. Thats terrible: my E8600 is still on top: it runs at 4.0Ghz with 1.16v on a watercooled setup with 4x120mm fans at 1600rpm. we are talking less than 30dB of noise and less than 55w of power consumption. At 1.25v my E8600 reaches 4.25Ghz and would go a little further if wasnt for the 4 sticks of ram burning the NB. no reason to exchange systems before the 32nm parts arrive. The ability to achieve high clocks with low voltages is crucial for a good system: not only will it consume less power, but it will also be quieter, and that is a point for choosing sub-65w dual-cores in gaming rigs.papapapapapapapababy - Tuesday, September 8, 2009 - link
honestly... i lol at all the core i7 core i5 "GAMERS"( and their punny 23 lcd with shitty TN panels) also LGA1366? LGA1156? and 285$ for a shitty motherboard? XD I have a better proposition for you INTEL. how about u SUCK MY BALLS XD. MKAY? the story: my old man needed a gaming setup ( mostly simracing) So i bought the cheapest E7200 i could find (oc3.2GHZ), 4gb of ram, the cheapest intel mobo i could find -g31- ( not even pcie2) and gave him my 4770 ... the price? ridiculously cheap... almost nothing. and with all that extra money i saved i got this > a nice 42" HDTV with a perfect s-ips panel and low 1366 X 768 resolution, and a g25 wheel.
btw, the framerates? i never, ever drop below 30fps. ALWAYS 60FPS NO MATTER WHAT, ( with nice 8xAA) XD so the best gaming cpu? the cheapest !
erple2 - Tuesday, September 8, 2009 - link
Interesting. Which 42" LCD TV did you get that has a S-IPS panel? Also, a 23" panel at about 3 feet looks bigger than a 42" screen at 6 feet.papapapapapapapababy - Tuesday, September 8, 2009 - link
LG. btw a 23" TN lcd looks like shit no matter how you look at it.C'DaleRider - Tuesday, September 8, 2009 - link
My, aren't you special?papapapapapapapababy - Tuesday, September 8, 2009 - link
yes, i know! btw enjoy your small screen gaming, mr sheep XDchrnochime - Tuesday, September 8, 2009 - link
I'd say the same about that barely big enough 42" LCD, but then again why bother...papapapapapapapababy - Tuesday, September 8, 2009 - link
my bad i meant this > E7300 3.2ghz (+ a cheap 24$ modded heatpipe cooler... 14 dba XD)