The new AMD Phenom II X6 1090T is the second hexa-core desktop CPU to hit the streets, following on from the Intel Core i7 980X Extreme Edition.
That statement of fact could make it sound as though AMD is trailing in Intel’s wake, where in fact there has been a deal of back and forth between the two companies. AMD led Intel by moving the memory controller from the chipset to the CPU core and ditching the front side bus in favour of Hyper Transport. Intel has Hyper Threading and Turbo Boost and has consistently been the first company to deliver each new fabrication technology. Intel employed 45nm for Core i7 and Core i5 and moved to 32nm for the Clarkdale Core i5 with integrated graphics and also for the Core i7 980X. Reducing the size of the transistors was a necessary move to squeeze in the extra two cores as the Core i7 die had no free space.
By contrast AMD appears to have had a relatively simple time when it built the Phenom II X6 1090T, as it didn’t need to change the 45nm SOI process to squeeze in two extra cores. We can only conclude that Phenom II X4 has a fair amount of space inside the core.
Indeed the only obvious change that AMD has made is to reduce the speed of the new hexa-core from that of the fastest quad-core. The Phenom II X6 1090T runs at 3.2GHz and has a 125W TDP while the 3.4GHz Phenom II X4 965 has a TDP of 140W.
The other change is the addition of that T suffix, as AMD has introduced Turbo CORE which is a dynamic overclocking process that happens on the fly. We may have misheard what the guy said during the briefing call but we made a note that Turbo CORE works ‘automagically’ in the background. Whether the quote is accurate or not we like the word.
Intel’s Turbo Boost raises the CPU speed in steps depending on whether it has one, two, four or six cores working hard, but essentially varies the core speed while remaining inside the designated thermal envelope.
Turbo CORE does something similar so if three cores (or fewer) are working, the CPU enters a ‘boost-eligible’ state and Turbo CORE raises the clock speed by up to 500MHz. If four or more cores are working the clock speed remains at the stock speed.
The new Phenom II X6 uses the same Socket AM3 as existing models of Phenom II, so provided you have a BIOS update you can expect the new hexa-core CPU will be a drop-in replacement, however we understand that the Turbo CORE feature is unlikely to work in older motherboards. To be on the safe side you’ll want a motherboard with the new AMD 890FX chipset that supports SATA 3.0 alongside SATA 2.0, and very probably comes with USB 3.0 as well.
At present AMD wants to keep the focus on its two new hexa-core models, the 2.8GHz Phenom II X6 1055T and the 3.2GHz Phenom II X6 1090T. It makes the point that its CPUs (which cost £160 and £240 respectively) are considerably cheaper than the Core i7 980X which costs £890. That’s true enough but it’s something of a red herring, as the merits of a hexa-core CPU are questionable.
Our testing of both the Core i7 980X and the Phenom II X6 1090T shows that the extra two cores deliver no benefit in benchmark tests such as PC Mark05 and Far Cry 2. Frankly we need some persuasion that even a quad-core CPU offers any benefit over a dual-core CPU for day-to-day use. The situation changes completely in a CPU intensive task such as video rendering or DVD encoding as we saw when we ran Cinebench. Unfortunately Core i7 980X trounces Phenom II thanks to the extra virtual cores that are provided by Hyper Threading, so the Core i7 980X scored 26,887 while the Phenom II X6 1090T scored 18,243.
We overclocked both our Phenom II X4 965 and the new X6 1090T to very similar speeds of 3.83GHz and 3.85GHz which delivered stacks of performance. In regular use the two systems have the same power draw figures but when we overclocked them, the quad-core system figure rose to 235W while the hexa-core draws 280W. That’s an extra 45W for the CPU.
Over the course of the next couple of months AMD plans to release two more hexa-core CPUs with a lower 95W TDP as well as a number of Phenom II models with two, three and four cores. On the face of it that sounds a bit predictable and possibly a touch dull but we’ve heard an exciting rumour. Apparently some of the unreleased models are based on the same CPU core as the new Phenom II X6 which means there is the potential to unlock the extra unused cores.
The other point is that we have to assume that the new CPUs will drive down the cost of a quad-core Phenom II towards £100, which sounds very promising.
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