Nehalem FAQ: The Straight Answers On Intel's New CPUs
Unless you are a completely irrational Hector Ruiz groupie or have been living on Mars for the past year, you've likely heard about Nehalem, Intel's next generation processor architecture. There has been a lot of information floating around the internet about this new CPU, much of it contradictory or just plain wrong. Let's try to set the record straight now with as much legitimate and generally confirmable information as is available at the time of writing.
Is Nehalem just a souped up Penryn?
Nehalem is essentially a completely new family of Intel processors which have brought back Hyper Threading, feature an integrated memory controller (yes, AMD did that first) supporting DDR3 RAM, and have done away with the Front Side Bus (FSB) through Quick Path architecture (in an implementation not too different from AMD's Hyper Transport) which allows for 25.6 GB/sec link: double the bandwidth as the X48 chipset's 1.6 GHz FSB. Nehalem also can dynamically manage darn near everything: power, threads, cache, cores and bus.
Will Nehalem work on my current motherboard?
No chance. A total of four new sockets with lots more pins on the motherboard will make every version of Nehalem incompatible with any LGA775 motherboard on the market.
Is Nehalem just one CPU?
Like Penryn and Conroe before it, Nehalem is a family of CPUs. They start out with the top of the line Beckton which is a monster 8 core processor which with Intel's new and considerably improved HyperThreading will present 16 (gasp!) CPUs in your Task Manager, but is designed for quad socket servers so look forward to seeing 64 CPUs in that Task Manager window!!! The rest of Beckton's specs read like Godzilla's personal processor: 24 MB of shared L3 cache, 4 x Quick Path Bus Interface, requiring Quad Channel FB-DIMM2 fully buffered memory and residing on a gargantuan LGA1567 socket which more than twice the pinouts as the current LGA775. We are supposed to see Beckton in Q2 2009 and as it is intended exclusively for the MP server arena, but you can bet that there will be a few gamers with Gold Visa Cards that will snap these puppies up. Regular mortals will have to content themselves with 4 core Nehalems many of which have Quick Path only a measly 8 MB L3 cache and teeny tiny LGA1366 sockets (yeah... teeny...). These CPUs will use dual and/or triple channel DDR3 (mercifully unbuffered) and come in the Gainestown (DP server) and Bloomfield (high end desktop) flavors. Below these mighty superprocessors you'll find Clarksfield (high end laptop) and Lynnfield (middle range desktop), which are quads with 8 MB L3 cache and then Auburndale (middle range laptop), and Havendale (low end desktop) which are just plain vanilla dual core CPUs and have a small 4 MB L3 cache. All of the CPUs below Bloomfield and Gainestown are stuck with the older DMI x 4 / x 2 PCI Express 2.0, so no Quick Path for them. They will also use smaller sockets, as the mobiles will use mPGA 989 and the other desktops will use LGA1160. Yes, Virginia, the days when Intel could be counted upon for one socket for desktops (LGA775) and another for servers (LGA771) are long gone and never to return.
Is Nehalem a 45 nm or 32 nm CPU?
This question has confused a lot of people so let's set the record straight. Nehalem is a 45 nm processor. What Intel has announced is that they will be optically shrinking the Nehalem architecture some time in 2009 to 32 nm but that processor will not be called Nehalem at all but Westmere. Much of the confusion arises from the fact that on some earlier roadmaps, Intel called the Westmere by the name Nehalem-C. Westmere will boast AES-NI which will encrypt/decrypt three times faster than current AES and may arrive with integrated graphics (I know, I know... AMD Fusion... zzzzzzzzzz).
What is Sandy Bridge?
It's a bridge in Singapore. It's also the successor to Westmere and/or Auburndale/Clarksfield depending on whether you're referring to the 22 nm version or the 32 nm one. There's also a CPU named Gesher floating around in the future but it's a bit early for too many more solid details.
What is Tolapai?
It's Intel's System On A Chip that will come with darn near everything you need except a hard drive to make a complete system. More details on that are expected later in 2008. It's not in the Penryn or Nehalem lineage.
When is Nehalem coming out?
Expect the first expensive Extreme versions of Bloomfield and Gainestown around November 2008. Following Intel's practices as demonstrated in the QX9775/9770/9650, expect to pay around $1500 for the first Nehalems. By around May of 2009 watch for a flurry of the other Nehalems to hit the shelves and the very expensive processors to drop in price by about half.
What kind of performance increase can we expect?
If you're running single threaded applications you are going to bash your head against the wall and wonder if Intel is pulling a fast one on you. Nehalem is not overly well optimized to do much of anything with single threaded apps, which represent most of the bulk of the software sold out there in cyberland. At most you will see about a 10% performance increase clock per clock, quad core per quad core. So a Bloomfield running at 2.66 GHz will outrun a Q9450 by roughly 10% on benchmarks that involve single threads. However, feed the Bloomy a blooming multithreaded app, and watch it leave the Penryn in its trail with up to double the performance. Gimme a Bloomfield, let me load it up with Triple Channel DDR3 and let me Photoshop until my eyes fall out! I can hardly wait!
Will Nehalem run at much faster frequencies than Penryn?
Surprisingly, Nehalem will likely top out around 3.4 or so GHz, not too different from the Penryn series. It's the various other architectural improvements which will account for the awesome performance edge.
How will Nehalem overclock?
Badly. There is some info leaking out that Intel has taken various steps to keep OCers from working their evil magic on their processors. Whether that sticks when it comes time to ship the CPUs only Intel knows and they're not talking.
What about power consumption?
You're buying a desktop processor, you're not thinking about stocking a 5,000 server farm with four Becktons per motherboard. The performance per watt is better than Penryn, but in common everyday usage that difference on your electricity bill is wholly insignificant.
Should I wait for Nehalem?
Whether to buy now or wait for "the next big thing" is a question computer users have been asking themselves since the Apple I. Since mainstream Nehalems that will be both generally available and have dropped down to reasonable street prices are not likely to surface before Summer 2009, it all depends if you can keep your old system working to your preferences until then. Intel's current 45 nm quads, and even the venerable 65 nm Q6600 will be viable processors well into 2010.
Is AMD Deneb comparable to Nehalem?
AMD's 45 nm CPU (if it ever reaches production) will be barely competitive with current 45 nm Penryns. Team Green is so far out of the running on this race that they're being lapped over and over and over and over and....