The Core 2 Quad and Core 2 Extreme are the most powerful CPUs in Intel's line-up. As the name implies, Core 2 Quad processors all have four physical cores, while the Core 2 Extreme range includes one dual-core processor - the X6800 - as well as the quad-core QX6000 and QX9000 ranges.
Core 2 ExtremeIf, on the other hand, you're after maximum performance, look to the Core 2 Extreme series. These chips are based on tweaked "XE" versions of the Conroe, Kentsfield and Yorkfield cores, running at clock speeds considerably in excess of their standard counterparts. The Yorkfield-based QX9770 goes as high as 3.2GHz, while the fastest Core 2 Quad with that core runs at 2.83GHz.
Core 2 Extreme processors are also fully multiplier-unlocked, so you can increase the clock speed as high as your motherboard will allow. There's no guarantee that your CPU will be stable above its stated speed, but the appeal for enthusiasts is obvious.
The problem with the Extreme range is immediately apparent from our graph on p88. It's normal to pay a premium for top performance, but the Core 2 Extreme series takes that principle to absurdity. The Core 2 Extreme QX9650 costs over £200 more than the Core 2 Quad Q9550, for a performance boost of some 2%. This month's most powerful processor, the QX9770, will set you back a jaw-dropping £792 exc VAT. Higher clock speeds may mean lower yields, but it's hard to avoid the conclusion that Intel, knowing it has no competition in this area, has mercilessly set its prices to take maximum advantage of enthusiasts and number-crunchers.
So, despite peerless performance, it's hard to recommend any Core 2 Extreme processor. If you absolutely must have the fastest processor on the block, it's the only game in town, but you'll pay through the nose for modest performance improvements over the Core 2 Quad.
In turn, the Core 2 Quad series suffers from a similar criticism in relation to the Core 2 Duo. If you can really make use of four cores then go ahead, but for everyday Windows computing the effective performance boost simply isn't enough to justify the price increase over the Core 2 Duo E8000 series.
Verdict
These high-end processors deliver maximum performance, but at a heavy price.
Author: Darien Graham-Smith
PC Pro Online