Ivy Bridge Desktop Lineup Overview

It's that time of the year. Once again, Intel's roadmaps have been leaked and we get to see what Intel has in store for us in 2012. I find the first bits of concrete info like frequencies to be the most interesting as they tell us what's really coming and allow us to analyze what to expect. So, let's see what the desktop Ivy Bridge lineup holds inside.

In case you need to refresh your memory about Ivy Bridge, you can consult our Ivy Bridge Architecture Exposed article (and check other content under our Ivy Bridge tag). However, we'll give a quick overview of the main points. Ivy Bridge is a die shrink of Sandy Bridge, from 32nm to 22nm. In Intel language, this is a "Tick", although for the graphics side, this is actually a "Tock" (i.e. new architecture). Ivy Bridge will also use Tri-Gate transistors and will be socket compatible with Sandy Bridge, so you won't need a new motherboard if you have a SNB based system already—just a BIOS update.

There will be new 7-Series chipsets, though, with support for USB 3.0 for example. The first details of Ivy Bridge leaked in May, and the latest roadmaps suggest an April 2012 release. Without further ado, let's take a look at what standard voltage Ivy Bridge CPUs are planned.

I think there is at least one typo. It doesn't make sense that i7-3770 has base frequency of 3.4GHz, whereas i7-3770K has 3.5GHz, yet they share the same Turbo of 3.9GHz. Turbo Boost works by increasing the CPU multiplier by a set amount of bins, and all the other CPUs have a maximum of five bins. We'd expect the i7-3770 to have a base frequency of 3.5GHz to follow the pattern of the other CPUs, not to mention it shares a name with the i7-3770K (the K indicating an unlocked multiplier). It could be right, and it's only 100MHz regardless, but it was a bit conspicuous. Anyway, that's it for typo-hunting; let's look at the big picture.

As a whole, the planned Ivy Bridge lineup looks a lot like the current Sandy Bridge lineup. There are a total of eight CPUs, which is actually two more than what the initial SNB i5 and i7 lineup had. Two of these CPUs have an unlocked CPU multiplier (K-Series), and two are i7s and have Hyper-Threading enabled, giving them a total of 8 threads. The frequencies are also fairly similar. Overall, IVB seems to provide a 100MHz boost over SNB, although the new i7-2700K reaches the same frequencies as i7-3770(K). It appears that all desktop i7 SKUs will use the better graphics. At first I thought this was a typo but after looking at the low power specifications (below) it started to make sense.

Not everything is the same, though. The trick of Ivy Bridge is its power usage. The TDP is down from 95W to 77W, which is a 19% decline. For years, Intel and others have been pushing for higher and higher performance with roughly static power use, but that has changed of late. Consumers have noticed that you can buy a relatively low performance ARM-based tablet and it can still run the tasks that most people do, but you get a device that is silent and has long battery life. For desktops, power efficiency isn't as big a deal, but it plays a huge role in laptops. I would say the reduction in TDP is the main reason why the specifications (not performance) are so similar to Sandy Bridge. If Intel had kept the 90W TDP, higher frequencies would have been likely and we might have even seen a hex-core part without a loss in frequency, but we'll save that discussion for another day.

There's one notable omission right now: the roadmap includes only i5 and i7 CPUs with no mention of i3. However, i3 is not gone—there will be an i3-3200 series. It's dual-core with Hyper-Threading and no Turbo Boost, very similar to the current i3-2100 series. We can't say for certain why its specifications are not listed, but it's likely that Intel will release the quad-core parts first and the dual-core parts will follow a month or two later, just like what we saw with SNB. It's also possible that there will be fewer i3 models than in the SNB lineup because of the two extra i5 models, but that's speculation.

PCI Express 3.0 is also missing from the info we have seen, but there's nothing on the PCIe version. The 7-series chipsets will have eight PCIe 2.0 lanes, that's known, but every slide concerning the PCIe lanes of the CPU refers to them as PCI Express, nothing else. The reason for the lack of version information might be the same as in SNB-E: there are no public PCIe 3.0 devices, so Intel can't guarantee 3.0 speeds. On the other hand, Intel doesn't want to list PCIe as 2.0 in IVB slides because we will most likely have PCIe 3.0 cards by the release of IVB platform. Anyway, IVB should provide us with 16 PCIe 3.0 lanes, which is quite evident if you look at the "Ivy Bridge Ready" motherboards.

The Low Power Ivy Bridge

The low power family has grown by four SKUs, from six (SNB) to ten (IVB), and we are still potentially missing some i3 models. One of the additions is the i7-3770T, the first T-series i7 CPU. It could prove to be a very interesting chip for low power desktops because it packs in four cores and Hyper-Threading and sports a very aggressive Turbo Boost range, all in a 45W TDP. That actually sounds a lot like what we've seen from the mobile SNB parts. The other significant addition is the i5-3475S; the specs are the same as the i5-3470S but the GPU is the faster HD 4000 instead of HD 2500. All the low power SNB CPUs used HD 2000 graphics, so the use of better graphics on a low-power desktop part is a new move. The remaining low-power models fill in the gaps with no real surprises.

Looking at the big picture, the standard voltage chips concentrated on reducing the TDP, so that definitely puts more pressure on the low-power chips. We'd even go so far as saying that the need for the S-series CPUs is questionable, as they're only rated 12W (16%) lower than the standad chips. The clock speeds are quite high in the S-series chips, sure, but recommending the S-series over regular chips will be hard, especially if Intel continues to charge a significant price premium for their low power models. We would have liked a further reduction in TDP on the low-power parts, e.g. make the S-series 55W and T-series 40W/30W at the expense of a couple hundred MHz. That way the lineup would have more differentiation, but in the end the roadmap is what it is.

The Graphics

Graphics is one area where Intel has put in a lot of extra work in Ivy Bridge. While the CPU core count remains the same, the IGP gets a boost. The EU count is up from 12 to 16 in the high-end version (HD 4000); HD 2500 has an unknown number of EUs, but 8 EUs seems the most likely. The new IGP also features support for DirectX 11, bringing it up to feature parity with AMD and NVIDIA parts (though we'll still take a "wait and see" stance on the drivers). In our Ivy Bridge Architecture article, Anand mentioned that IVB should offer nearly twice the GFLOPS per EU that SNB offers. Intel has been claiming improvements of up to 60% in graphics performance, which sounds plausible given the clock speeds and EU counts. We will take a deeper look into the performance in a separate article soon.

Wrap-Up

Overall, there aren't any big surprises in the lineup. The mobile lineup should be a lot more interesting because Ivy Bridge has clearly been designed with power efficiency in mind, and that is what matters in laptops. Unfortunately, the data we have right now is only for desktops, so we'll have to wait leaked mobile roadmaps. We'll leave off further investigation and analysis of the Ivy Bridge roadmap for now, but we'll return with a couple more articles looking at other areas in the next week or so.