As we’ve seen, though LGA 1155 CPUs and motherboards are incredibly quick and outrageously overclockable, and can put their LGA 1366 stablemates to shame.
Processors at the top of the range such as the Core i7-970 and Core i7-980xExtreme Edition sport sic Hyper-Threaded cores, allowing them to perform better than LGA 1155 CPUs in highly multi-threaded applications. It’s to this elite group of processors that Intel’s new release, the Core I7-990X Extreme edition belongs.
As the i7-990x
is a part of Intel’s Extreme Edition range of processors, it sports an unlocked CPU multiplier, which should allow you more freedom when overclocking the chip. For example, if you reach the QPI limit of your motherboard when overclocking, an unlocked processor allows you to increase the multiplier so that you can push the processor as far as possible.
Sitting at the top of Intel’s range, the i7-990X is now the fastest LGA 1366 processor, with a stock speed of 3.6GHz; this is a slight increase over the i7-980X, which runs at 3.33GHz. This higher default frequency has resulted in an equivalent increase in the theoretical maximum speed to which the processor can turbo boost, meaning that the i7-990X should be able to reach 3.73GHz when it’s only being loaded on one core.
Unfortunately, this is where the difference between the two processor ends, as in every other respect the i7-990X is identical to the i7 980X. It has the same 256KB of level 2 cache per core and the same large pool of 12MB Level 3cache. It also impressively, has an identical maximum TDP rating of 130W and is made on the same 32nm-scale production process as the other LGA 1366 processors. The i7-990X is even based on the same B1 stepping as its predecessor, meaning that there haven’t even been any significant tweaks or changes to the die design for this new CPU.
Given the frequency advantage to the i7-990X has over the i7-980X, it was no surprise to see it edge out its older stable mate in our entire stock speed test. In Cinebench 11.5, it was 0.25 points ahead of the i7-980X, a result that was mirrored by a slight 0.117 of a second advantage it demonstrated in WPrime. The i7-990X also demolished Intel’s LGA 1155 CPUs in these tests, thanks to its 12 processing threads.
Its higher stock clock speed and extra turbo boost headroom also meant that the i7-990X managed a slight lead over the i7-980X in out Media Benchmarks.
Its overall score of 2,145 was 7 percent faster than the 2,002 points of the i7-980X, which is an excellent result given the 4 percent nominal clock speed advantage to the i7-990X. however \, the i7-990X faced stiff competition from the top-end Intel Sandy Bridge CPUs, only a narrowly beating the i5-2500K and losing out to the i7-2600K- clearly Turbo Boost worked well on the new CPU.
Games showed less benefit from the extra clock speed on offer from the i7-990X, with crisis showing no sign of a frame rate increase. This meant that the i7-990X lagged slightly behind the vastly cheaper LGA 1155 based i5-2500K and i7-2600K.
Next we tried overclocking, starting an aggressive 1GHz overclcok, which the i7-990X easily took in its stride. Encouraged by this success we continues to push the chip further, eventually settling on a stable overclock of 4.6GHz with a QPI of 200MHz and a 23x CPU Multiplier. This represents a 1.14 GHz boost over the 17-990Xs stock speed. The 17-990’s overclcok is also superior to the 1.07GHz stable overclcok of the i7-980X
To stabilize this overclock we had to pump 1.412V through the CPU, 1.96V and 1.375V through the CPU PLL and QPI/DRAM voltages respectively and 1.3V and 1.2V to the IOH and ICH. We also had to set the UCLK frequency to 3,208MHz and the QPI link frequency to 7218MT/s. we had the CPU happily booting at just under 4.8GHz, but couldn’t get this overclock stable using air cooling, this is a good sign that could be unlocked with more exotic methods of cooling.
At these speeds, the i7-990X demolished our test suite, clocking in both Cinebench 11.5 and WPrime. We also saw a healthy 23 per cent increase in the CPUs overall Media Benchmarks score, with an impressive 2645 points. However the i5-2500K returned a score of 2687 when overclocked, while the overclocked i5-2600K scored 2702
The i7 -990X’s power consumption during the test proved interesting, as it drew far less power that the i7-980X. This is due to the lower 1V vid of our sample which places the CPU at the lower end of the range of vids with which the LGA 1366 CPUs ship.
We lauded the i7-980X when it launched, as it justified its exorbitant price with its two extra cores with other LGA 1366 CPUs. The i7-990X shares these features but enters a changed market, due to Intel’s own LGA 1155 CPUs.
The i5-2500K is roughly as quick as, and sometimes quicker that the i7-990X in all but the most heavily multi-threaded tasks. Its also very overclockable .as a result, only those running professional-grade multi-thread-optimized application should consider the i7-990X and even then you’d better of buying an i7-980X which is nearly as fast and a lot cheaper.