

Ever since Intel did the first Haswell graphics explainer, there’s been talk about just how much additional performance the company would deliver with its new lineup of graphics processors. Ivy Bridge, after all, was a major improvement over Sandy Bridge — so much so that Intel talked up its “Tick Plus” model as a key component of the first-generation 22nm processor’s appeal.

We’re still barred from talking about Haswell’s GPU performance directly, but Intel has released new branding information and some early performance figures. If you plan on buying a Haswell-based system, you’ll want to understand these performance levels and how the new brands are being used.

The top-end Intel graphics products are now known as Iris Pro and Iris. Intel Iris Pro systems are based on the company’s GT3e graphics solution. That’s the chip with an onboard eDRAM frame buffer (pegged at 128MB by RealWorldTech). The slide below describes the differences…

Intel SKUs

As of this writing, Intel’s Iris Pro 5200 GPUs will only be available in 48W mobile SKUs. There are two further flavors of GT3 — Iris 5100 and Iris 5000. The Iris 5100 parts are intended for 28W mobile processors while the 15W chips all use the Iris 5000. Intel isn’t revealing clock speeds yet, but the difference between Iris 5100 and 5000 is going to be boost/turbo clocks.

How do these SKUs impact desktop parts? They basically don’t. Intel will offer one BGA-based solution (the R-series) with GT3e graphics. All of the other desktop chips will use the HD 4600-4200 SKUs. These top out at 20 EUs (Execution Units), as compared to Ivy Bridge’s 16 EU’s. Thus, the desktop performance increase in graphics should be 15-20%. That’s reasonable, if not particularly exciting.

The performance per watt trade-off

Intel’s exceedingly limited performance numbers suggest the performance trade-off in mobile is significant.

Intel performance 15-28W

We’re going to ignore 3DMark 6 (because no one cares), and look at the 3DMarkVantage and 3DMark11. Forget the far-right bar for the 28W part, for a moment, and focus on the middle. That’s the Intel Core i7-4650U, a 15W part with (presumably) Iris 5000 graphics. Factor in the 2W TDP decline, and the performance boost between the new Haswell chip and the older Ivy Bridge CPU is actually excellent. Moving to GT3 picks up ~25% in one benchmark, 50% in the other.

While Intel is obviously going to cherry pick results, these should map to real-world games. GT3 is more than twice the size of GT2 (40 EUs vs 16) and one reason Intel went to the wider array is because it could down clock the graphics cores and save power as a result.

The i7-4558U is a different story. Forget Ivy Bridge for a moment and look at the 4650U vs 4558U comparison. The 4558U is only 1.32x as fast as the 4650U in 3DMark Vantage, and 1.5x as fast in 3DMark11 — despite drawing nearly 2x as much power. This suggests that GT3’s power consumption benefits are narrowly defined — the array will sip power if you keep clock speed constrained, but raising the clock speed bar will quickly turn the tables on power consumption.

Next page: More analysis, and what did Intel actually tell us today?