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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JonnyDough - Tuesday, September 8, 2009 - link
Anyone who buys a $1000 CPU has more money than brains. If you wait six months you can buy a newer budget processor for about 1/15 of the cost, overclock it and obtain the same result. I would think that $925 would be more valuable to someone with sense than bragging rights for six months. I was taught that when people brag they are vain morons. A person's value should not be estimated by the stuff they have, but by the choices they make. We all get a lot in life, it's what you do with it that sets you apart. Unfortunately our society is ruled by greed and capitalism. I choose to speak against that. If you have a problem with that, I suggest you take it up with the greedy capitalist complaint department. They don't care either.max347 - Wednesday, September 9, 2009 - link
Hmm, it would seem to me that someone who has $1k to spend on a cpu probably has "alot of brains", hence the better-than-average financial position, enabling the purchase in the first place.Also, you equate greed to capitalism. This is clearly false. People get what they work for in a capitalist society. I am not saying it is perfect, though what would be a better alternative? People are not going to be financially equal, as some work harder than others. To dispute this would demonstrate a lack of experience...to say the least.
Someone chooses to get the best. It's their money, their choice. But you're right, you should probably call them a greedy capitalist.
fullcooler - Wednesday, September 9, 2009 - link
wow, you said that way calmer than I would have. very classy reply to a young leftist. perhaps when obama passes the "free $1000 cpu's for lazy punk leftists" plan, you and I can pay for his cpu,and he wont be a sellout to the man by working for it.imaheadcase - Tuesday, September 8, 2009 - link
I hate people who used that phrase "Has more money than brains". Doesn't it stand to reason, they have brains..if they have more money than you to buy the CPU... lolJNo - Tuesday, September 8, 2009 - link
Not necessarily - they might have inherited the money for example.Maybe you have more money than brains too...
JonnyDough - Tuesday, September 8, 2009 - link
Yep. These people sound like they have no idea how to be frugal with money. It's ok though, a fool and his money are soon parted.lyeoh - Thursday, September 10, 2009 - link
Stop doing that ok?If you discourage too many rich/stupid people from buying the bleeding edge stuff it just makes it harder for the rest of us.
Poor folks like me need those rich guys to rush out and buy the expensive CPUs (and GPUs etc) and work all the bugs out, get the production line ramped up etc.
Then 6-12 months later we have good and cheap stuff to buy.
The best CPU costs way less than an expensive house anyway, so it's not like he's going to cause some sort of nation wide or global financial crisis.
VaultDweller - Tuesday, September 8, 2009 - link
Maybe they don't know how to be frugal with money.Maybe they don't NEED to be frugal with money.
Sure, a fool and his money are soon parted - but so is a brilliant rich man who has more money than he needs.
niva - Tuesday, September 8, 2009 - link
I disagree with your first statement. There are people who simply want the best/fastest and will pay the money for it. Only in the last 3 or 4 years has top of the line performance become relevant only for gaming. A few years ago all sorts of pros needed the fastest they can get their hands on and purchases like $1k per CPU were actually justified.Now just because you can't afford a 1k CPU and never have been, doesn't mean people who buy such things are morons. Same goes for buying a Ferrari by the way. Quit being a jealous putz, thanks!
JonnyDough - Tuesday, September 8, 2009 - link
When you compare value ratios, yes. A $1000 CPU is soon worth about $75. A Ferrari sold as parts is worth about 1/15 of the price also. I didn't think I'd have to spell it out for you.