Ivy Bridge: Intel Core i7-3770K
Ivy Bridge: Intel Core i7-3770K
Initially, Intel presented us with an Ivy Bridge lineup that consisted of 7 regular desktop models and 7 low-wattage variants. However, a few weeks ago that lineup was reduced 5 and 4, respectively. We are assuming that Intel is merely delaying the launch of these now absent models, and that they will be introduced sometime in the future. So far we have gotten zero hints with regard to any Core i3 models, but we have to assume that dual-core/four-threads Ivy Bridge chips are also going to make their appearance sooner rather than later.
With respect to model names, we can't help but feel that Intel are not giving themselves much room to maneuver with Ivy Bridge LGA1155. While they might one day introduce an i7-3780K or 3790K part, they couldn't really go above that, lest it eclipse the "higher-end" Core i7-3820. What we are trying to say is that what you see is what you get with Ivy Bridge on the LGA1155 platform, there will not be much of an upgrade path. Haswell is the future for Intel, which is Socket LGA1150.
By transitioning to the new 22nm manufacturing processor, Intel has managed to increase the transistor count from 1.16 billion on Sandy Bridge up to 1.4 billion Ivy Bridge. This is about a 21% increase, which is not really that much, but what is truly impressive is that the die size has from shrunk 216mm2 down to 160mm2. That is a noteworthy 35% decrease, and as you will see in the later parts of the review that tiny die size caused some problems. Keep in mind that these are the figures for the full-blown quad-core + HD Graphics 4000 die, we fully expect that the dual-core and/or HD Graphics 2500 parts will have a reduced transistor count and die size as what the case with Sandy Bridge.
Despite AMD's Bulldozer being a bit of a flop, Intel is not really trying to take advantage of the situation, and the new Ivy Bridges processors are actually $3-4 cheaper than the equally positioned Sandy Bridge parts were at launch. Consumers are going to have to pay a premium for graphics power though, since the more powerful of the two IGP variants is reserved for the higher-end parts, which is a shame since it's those who buy the more reasonably priced parts that are most likely to forgo a discrete GPU and thus need the most powerful IGP possible. We strongly suspect that Intel will eventually bundle the HD Graphics 4000 with the mainstream processors sometime down the road, just like they did Sandy Bridge and the Core i3-21x5 parts.
As we mentioned in the introduction, the flagship of the new lineup is the Core i7-3770K. It is a K-series model, which means that it has unlocked multipliers, and it features a 3.5GHz default clock speed, Turbo capabilities up to 3.9GHz, and 8MB of L3 cache. All these figures are essentially identical to the Core i7-2700K, which has the same 3.5GHz default / 3.9GHz Turbo clock frequencies, and identical L1/L2/L3 cache sizes. Although the basic cache sizes have remained the same since the Nehalem architecture, the increase in the cache operating frequency and associativity has resulted in much higher bandwidth and lower latencies on Ivy Bridge. Another performance advantage in IVBís favour is the new DDR3-1600 memory interface, which can provide up 25.6GB/s of memory bandwidth, up from 21.3GB/s on Sandy Bridge. Much like Sandy Bridge-E, the integrated PCI-E controller now supports PCI-E 3.0, but Ivy Bridge chips still only have 16 dedicated lanes for the graphics slots.
The whole lineup features a 77W TDP, which is a very worthwhile reduction when compared to the previous 95W figure that was the standard for most of Intel's recent quad-core mainstream parts. This lower TDP is double edge sword though, at least for performance enthusiasts. On the one hand, it allows for lower power consumption and (theoretically) cooler operating temperatures, but on the other hand it definitely limits the potential core clocks. Releasing a next generation flagship part at the same clock speed as the previous generation's top-end model is slightly underwhelming, especially given the minimal core improvements and the move to a cutting-edge manufacturing process. As we explained at the top of the page, we also aren't really confident that Intel will be releasing much higher clocked models, although that is just speculation on our behalf.
By the way, those of you who put a heavy emphasis on lower consumption or simply want to build a cool-running but very powerful HTPC will be glad to know that Intel is also releasing a couple of low wattage variants too.
There is nothing fundamentally new on the packaging front, Ivy Bridge processors will ship in exactly the same box as Sandy Bridge models. Although Intel did not provide us with a stock cooler, we suspect that they will look this this.
As you might have expected Ivy Bridge LGA1155 processors look exactly like the Sandy Bridge one's did, and are thus also almost indistinguishable from the previous LGA1156 Clarkdale and Lynnfield models.
Based on the digits on the integrated heatspreaders, we can determine that our chip was made in the 6th week of 2012. That is much 'fresher' silicon then we are used to seeing from Intel, which might support the argument that they encountered a few bumps along the way when they started manufacturing on the new 22nm process.
On the voltage front we were very surprised to see that idle voltage was higher than what we have seen on both Sandy Bridge and Sandy Bridge-E. As you will see in the power consumption section, this ultimately proved to be irrelevant, and more importantly the full load voltage was about 0.10V lower.
The bus speed is still 100MHz, and as on Sandy Bridge there is not much overclocking headroom, only about 7-8%. This is because so many of the CPU's different parts are deriving their operating frequencies from this base clock, and since some are very sensitive to frequency changes, they can get out of whack very quickly.
As mentioned above, the cache structure is the same as on Sandy Bridge, although as you will see in the benchmarks it's now even faster and with lower latencies.
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