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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moronsworld - Saturday, September 26, 2009 - link
To all you morons that don't understand economics. amd gone = intel monopoly = intel processors overpriced. Plain and simple. Take an economy class or 2, you morons. AMD is a good company, just that Intel's processors are better at the moment. God too many morons in this world that are allowed to vote. We live in a society ruled by morons.TA152H - Tuesday, September 8, 2009 - link
Actually, you don't really know what you're talking about.On-die memory controllers are nothing new. The Nexgen 586 had it in the mid-90s. Intel just knew when to add it, and when not to. That's why the Core 2 blows AMD processors away, while being significantly smaller.
AMD instruction schedulers were behind Intel's Pentium Pro from 1995 until the Phenom II came out. It still doesn't have full memory disambiguation like Intel introduced with the Core 2, but at least the memory scheduling is now on par with the Pentium Pro. I'm not sure that something they like brought up though.
64-bit processing is also old hat, and really was just an extension of the 386 protected mode anyway, with a lot of Microsoft input.
The K8 wasn't really much of an architecture, it was a K7 with a memory controller, and a couple of extra stages for better IPC, that most idiots thought was for higher clock speeds. It was a failure, and was what put AMD in the situation where they are now. It was, generally, better than the Netburst, but then, is that such a high bar to get over? The problem was, they actually believed it was a good processor until the Core 2 relieved them of that misapprehension. The reality is, Intel's mobile chips were always better than the K8, but the damn fools made us buy the Pentium 4 for the desktop. To AMD's credit, at least they never made anything horrible like that, but, really, their primary claim to fame was based more on the terrible Intel design than a great processor of their own, and the fact Intel wouldn't let us use the mobile chips for desktops.
JonnyDough - Tuesday, September 8, 2009 - link
Please work on your English before replying to me in the future. Thanks.Aenslead - Tuesday, September 8, 2009 - link
So you *must* have perfect english to reply in these forums?Gosh, never saw that in the Terms and Conditions agreement when I created my account. So that means that anybody (or a nobody, like you) have a say on what other races and people from other countries that don't speak English as their first language, that LIKE READING and giving their opinion in a FREE MOFO OPEN FORUM, must do to post here?
You and your kind are pathetic.
JonnyDough - Tuesday, September 8, 2009 - link
I didn't say anything about having perfect English. You sir, are a troll. I just wanted his reply to be coherent. This is the ENGLISH version of DailyTech, there are other language versions. His post didn't even make sense, and yours was just trolling.ginbong - Wednesday, September 9, 2009 - link
I understood what he said, maybe you need to sharpen up your analytical skills and stop being a dlckhead on this hardware analysis website.Better yet, how about taking the money you have saved for your next PC upgrade and enrolling into Grade 1 again.
dastruch - Tuesday, September 8, 2009 - link
and you don't get it too... patheticjigglywiggly - Tuesday, September 8, 2009 - link
This is a hot cpu, except I want 6 cores + HT. 32nm... quads ahh yeah. I still don't like the i5, because I don't want two sockets on one brand at the same time. It just limits options, I am only looking at i7/i9, because I bought this qx6700 in 2006 for 1000$. It was a good purchase, because q6600s were a while away and they were 500$. I got my qx6700 to 3.85ghz, now it's at 3.5ghz stable. Curse you electromigration! Also curse you economy! I don't have enough money for a 6core+6HT 1000$ cpu again.JonnyDough - Tuesday, September 8, 2009 - link
*Laughs at the moron...Go buy a Ferrari and then wreck it and sell it for parts. That's essentially a larger scale version of what you did.
Lifted - Tuesday, September 8, 2009 - link
Huh? Buying a $1000 CPU is like wrecking a Ferrari?"Laughs at the moron"