Intel Ivy Bridge Core i7-3770K Review

Hugo has written a technical background feature on Intel's new Ivy Bridge family of Core i5/i7 processors but just in case you haven't read it here are the highlights;

the architecture of Ivy Bridge is closely derived from Sandy Bridge and uses the same LGA1155 processor socket, however the fabrication process has moved from 32nm to 22nm. In addition to making the transistors smaller, Intel has used its new 3-D Tri-Gate transistor technology to pack the transistors in tighter together.

The most obvious change to come from these advances is that Sandy Bridge Core i5/i7 has a TDP of 95W while Ivy Bridge has a TDP of 77W. That's a strong indication that Intel expects Ivy Bridge to have lower power consumption than Sandy Bridge and as it uses the same processor socket you can be sure that your existing cooler will fit the bill.

Inside the die Intel has updated the HD 2000 or HD 3000 graphics core (depending on the model of Sandy Bridge CPU) to HD 2500/HD 4000 with some extra shaders and support for OpenGL 3.1 and DirectX 11. Intel is rather excited about the updates to its graphics however I'm more interested in those 22nm 3D transistors and the reduced 77W TDP.

Testing, testing

You can use an Ivy Bridge processor with your existing 6-series chipset motherboard with H61, H67, P67 or Z68 chipset provided it uses ME8 firmware, but this will not deliver the maximum benefit of your new processor. In particular you need to use an Ivy Bridge chip in conjunction with a 7-series motherboard if you want to take advantage of the PCI Express 3.0 controller in the processor core. Remember, the PCI Express and memory controllers are in the Ivy Bridge core and not in the motherboard chipset.

We pitched our Core i7-3770K processor against a Core i7-2700K using an Intel DZ77GA-70K motherboard, 16GB G.Skill RipjawsZ DDR3-1600MHz RAM, Sapphire Radeon HD 7970 graphics card, Intel 510 SSD and 64-bit Windows 7 Professional.

The two processors each have a base clock speed of 3.5GHz with a Turbo Boost speed of 3.9GHz, have 8MB of cache and are quad-core models with Hyper Threading. The main difference, apart from the 22nm/32nm fabrication process, is that the new model has HD 4000 graphics and the older has HD 3000.

Performance and power

So we've got two processors with identical clock speeds and broadly speaking they deliver the same performance. In the synthetic benchmark PC Mark 7 the two systems delivered near-identical performance with 5,596 marks for Ivy Bridge and 5,455 for Sandy Bridge.

POV-Ray is a synthetic test that hammers the CPU and this showed both processors running the test in the same 193 seconds, however the Sandy Bridge system drew 150W at the wall socket while Ivy Bridge required 120W. That's a huge difference of 30W or 20 per cent however it is worth noting that both figures are impressively low for a high end gaming PC.

In the 3D Mark 11 and Unigine Heaven graphics benchmarks we saw the Sandy Bridge system deliver better performance than Ivy Bridge - in Unigine it was MUCH higher - which was an unexpected turn of affairs. At this point I'll go out on a limb and state that this feels like a failing in the benchmarks rather than a fault in Ivy Bridge. Once the new processor has been formally released you can bet your boots there will be updates to the software that levels the playing field and no doubt there will also be a flurry of BIOS and driver updates too.

While the performance figures may be a little confusing there is no doubt that Ivy Bridge consistently drew far less power than Sandy Bridge.

Overclocking these unlocked Ivy Bridge and Sandy Bridge processors on the Intel DZ77GA-70K is a simple matter of opening the UEFI set-up screen and jamming the Turbo Boost slider all the way to the right. This raises the maximum Turbo figure from 3.9GHz to 4.5GHz, which is a healthy extra dollop of performance for zero effort.

Interestingly the extra clock speed appeared to give Ivy Bridge an advantage over Sandy Bridge. The two processors had performed identically in POV-Ray at 193 seconds, but the overclocked Ivy Bridge finished the test in 158 seconds while the Sandy Bridge took 167 seconds. The power draw for Ivy Bridge increased from 120W to 170W while Sandy Bridge moved from 150W to 200W.

In both cases the overclocked CPU demanded an extra 50W and the Sandy Bridge drew 30W more than Ivy Bridge but there's no arguing with an extra 15-20 per cent performance. Intel doesn't appear to have made any changes to the Turbo Boost 2.0 feature and we'd say that was a wise move.

Those tests had been run with the Sapphire HD 7970 installed so now it was time to remove the graphics card and switch to the integrated Intel HD 4000/3000 graphics. The first step was to switch the power supply from our fairly lightweight Corsair CX500 to an even more weedy In Win 450W. It's something to do with the internal construction of power supplies and I often find that PCs with integrated graphics don't draw enough power to signal the PSU to come to life.

With the In Win installed the PC ran correctly and the first point to note is that the idle power draw only dropped by 10W which is an impressive reflection on the idle power consumption of AMD's latest Radeon graphics cards.

You can see the difference that the graphics make in the Unigine benchmark as the Ivy Bridge system only required 75W. Sandy Bridge HD 3000 graphics support DirectX 10.1 and cannot run the DirectX Unigine and 3D Mark 11 tests.

Although Ivy Bridge can run 3D Mark 11 Extreme the score was a laughable 218 marks so it is safe to say that gamers should continue ignoring Intel graphics.

The cost of Ivy Bridge

Intel is bringing in its new Ivy Bridge processors as a direct upgrade to Sandy Bridge so we expect to see the 3.5GHz Core i7-3770K on sale at £260, the 3.4GHz Core i7-3770 at £235, 3.3GHz Core i5-3550 at £169 and the 3.1GHz Core i5-3450 at £150. Expect to see chips hitting the market in limited supply in the next couple or weeks, with volume ramping up around June - so get your order in now.


If you already own a Sandy Bridge PC then it makes little sense to upgrade your existing processor but if you're buying or a building a new PC we have no doubt that Ivy Bridge is the only game in town.

Pros: Superb power efficiency, excellent performance, same price as Sandy Bridge

Cons: Requires a 7-series chipset motherboard to get the full benefit, integrated graphics still not great

Score: 9/10

Manufacturer: Intel

Price: £260 (estimated)