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
Lynnfield's Un-Core: Faster Than Most Bloomfields
A few years ago I had a bet going with AMD's Ian McNaughton. We were at an AMD event where the Phenom architecture was first being introduced and he insisted that the L3 cache was part of the memory controller. This didn't make any sense to me so I disagreed. Minutes later a presentation slide went up on a projector talking about how the L3 cache and memory controller were on the same voltage plane; that's what he meant. Ian laughed a lot and to this day he holds it over my head.
The moral of the story is in Phenom and later in Nehalem, the processor is divided into two parts. Intel named them the core and the un-core. The "core" of these multi-core processors is made up of each individual processor core and its associated private caches (L1/L2). The "uncore" refers to everything else: PCIe controller, memory controller, DMI/QPI and the L3 cache.
The uncore isn't as critical for performance but is made up of a ton of transistors; roughly 400 million in the case of Lynnfield/Bloomfield (more if you count the PCIe controller). In order to save power, Intel uses slower transistors that have lower leakage for the un-core. As a result, the un-core can't clock up as high as the core and runs at a lower multiplier.
Take the Bloomfield Core i7 975 for example. The core runs at 25x BCLK (25 x 133MHz = 3.33GHz), but the un-core runs at 20x BCLK (20 x 133MHz = 2.66GHz). The rest of the chips, including Lynnfield, have slower un-cores:
| CPU | Socket | Core Clock | Un-Core Clock |
| Intel Core i7 975 Extreme | LGA-1366 | 3.33GHz | 2.66GHz |
| Intel Core i7 965 Extreme | LGA-1366 | 3.20GHz | 2.66GHz |
| Intel Core i7 950 | LGA-1366 | 3.06GHz | 2.13GHz |
| Intel Core i7 940 | LGA-1366 | 2.93GHz | 2.13GHz |
| Intel Core i7 920 | LGA-1366 | 2.66GHz | 2.13GHz |
| Intel Core i7 870 | LGA-1156 | 2.93GHz | 2.40GHz |
| Intel Core i7 860 | LGA-1156 | 2.80GHz | 2.40GHz |
| Intel Core i5 750 | LGA-1156 | 2.66GHz | 2.13GHz |
Here's another area where Lynnfield is better than the lower end Bloomfields: its uncore runs at 2.40GHz instead of 2.13GHz. The exception being the Core i5 750, its uncore is stuck at 2.13GHz as well. Once again, only the "Extreme" Bloomfields have a faster uncore.
Lynnfield's Memory Controller: Also Faster than Bloomfield
Intel only officially supports two memory speeds on Bloomfield: DDR3-800 and DDR3-1066. Obviously we're able to run it much faster than that, but this is what's officially validated and supported on the processors.
Lynnfield is a year newer and thus gets a tweaked memory controller. The result? Official DDR3-1333 support.
Three Lynnfield memory kits (left to right): OCZ, Patriot and Kingston
The same sort of rules apply to Lynnfield memory kits that we saw with Bloomfield. You don't want to go above 1.65V and thus all the kits we've seen run at 1.5V for the stock JEDEC speeds or 1.65V for the overclocked modules.
Like Bloomfield, 1.65V is the max we'll see on Lynnfield
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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"