AMD Athlon 64 X2 4800+ Grange-over-Sands

If there's one thing you can count on in the PC industry, it's that when Intel launches a new CPU, AMD will also launch one, and vice versa. So after the launch of Intel's first dual-core CPU last month, the monstrous Pentium Extreme Edition 840, it's no surprise that AMD's first dual-core CPU, the Athlon 64 X2 4800+, has suddenly appeared.

The X2 also makes use of the latest Toledo core. The main improvements are support for SSE3 and a lower operating voltage, which means the CPU runs cooler, and could be very overclockable as a result. The Toledo core also has an improved memory controller, which should boost performance by about 1 per cent in memory-intensive applications, according to AMD. These optimisations are also found in the new Venice-core Athlon 64s.

Initially, there will be four members of the Athlon 64 X2 family: the 4200+ running at 2.2GHz with 512KB of Level 2 cache per core; the 4400+ running at 2.2GHz with 1MB of Level 2 cache per core; the 4600+ running at 2.4GHz with 512KB of Level 2 cache per core; and the 4800+ running at 2.4GHz with 1MB of Level 2 cache per core. Of course, being the power-hungry monsters that we are, we had to test the fastest model.

In fact, testing the X2 was easy, as AMD has made its new family of CPUs compatible with existing Socket 939 motherboards. This means you won't need to buy a new motherboard, as you're forced to do for Intel's dual-core CPUs. All you'll have to do is flash the BIOS to enable X2 support. Also, you shouldn't have to buy a new PSU or cooling hardware, as the top-end 4800+ has a TDP (Thermal Design Power) of just 110W, compared to 130W for the 840. That said, 110W is still a substantial increase over an Athlon 64 4000+, which has a TDP of 89W.



PERFORMANCE

As most applications are still single-threaded, in most cases the X2 4800+ should offer performance equivalent to an Athlon 64 4000+, as this also runs at 2.4GHz and has 1MB of Level 2 cache. In order to compare these two processors, we built a test rig comprising an Asus A8N-SLI Deluxe motherboard, 1GB of Corsair XMS 4400C25 RAM and a GeForce 6800 GT graphics card. Apart from the motherboard and RAM, this is the same configuration that we used to test the Extreme Edition 840 last month, so you can easily compare the benchmark results of the AMD and Intel dual-core CPUs.

Compared with the NetBurst architecture of the 840, the Athlon 64 has a short pipeline, which makes it weaker at computationally predicable tasks, such as video encoding. However, as many encoding applications are multithreaded, the addition of a second core goes a long way to offsetting this weakness. This was apparent in our TMPGEnc video encoding test, in which the X2 4800+ outperformed the 4000+ by almost 92 per cent, with a blistering score of 2.42. However, even this super-fast result wasn't enough to scare the 840, which scored 2.92. Clearly, if you're serious about video then the Intel processor is the one to buy.

The synthetic tests built into SiSoftware Sandra 2005 also highlight the differences between the two CPU architectures, with the 4800+ lagging significantly behind the 840 in the CPU Multi-Media Benchmark Float x4 iSSE2 test. However, in real-world, processor-intensive applications, such as 3D rendering, the 4800+ sped ahead of the 840. For example, our LightWave test, which renders a scene from 'Lost in Space', took almost 30 seconds less to complete on the 4800+.

Part of the reason for this could be the 840's low clock speed. Because of power and heat issues, Intel was forced to run the 840 at a comparatively low frequency compared with single-core Pentium 4 CPUs. However, as the Athlon 64 core produces considerably less waste heat, AMD has been able to take a different approach. By clocking each core at 2.4GHz, the X2 4800+ can compete with higher-clocked Intel processors, such as a 3.8GHz Pentium 4e in single-threaded applications. This was demonstrated by the storming average frame rate of 68.4fps in Far Cry at 1,280 x 1,024 with 2x AA and 2x AF - considerably faster than the 58fps of the 840. This means that the X2 4800+ will provide fantastic game performance immediately, while also taking advantage of multithreaded optimisations when they appear.

It's also worth noting that the X2 4800+ was 6 per cent faster than the 4000+ in Far Cry, possibly due to its enhanced memory controller and the addition of SSE3. It was also faster in our Paint Shop Pro image editing test, scoring 1.67 compared to 1.59, although both of these scores are still significantly ahead of the 1.34 scored by the 840.

Unfortunately, at the time of going to press, the BETA BIOS on the A8N-SLI Deluxe motherboard that we used to test the X2 4800+ didn't allow voltage adjustments, so overclocking was extremely limited.

Even so, we succeeded in raising the FSB from 200MHz to 220MHz, which upped the frequency of each core from 2.4GHz to 2.64GHz. This resulted in a worthwhile speed increase, boosting the overall Media Benchmark score from 1.80 to 1.99. This is slower than the 840, which scored 2.14 when overclocked to 4GHz, but with a decent BIOS, we're sure that the 4800+ could overclock much further.

CONCLUSION

Now that AMD has released its first dual-core desktop CPU, the 'multicore wars' have well and truly begun. As you'd expect, because of their very different internal architectures, the X2 4800+ has a number of advantages over the 840. For starters, the X2 4800+ consumes far less power and produces less waste heat than the 840, so it doesn't need a new PSU or cooling system. You also don't have to buy a new motherboard, so you can easily upgrade from a single-core Athlon 64 to an X2. This is a major advantage over the 840, which requires you to buy a new and expensive motherboard. Secondly, AMD has managed to produce a dual-core CPU that offers similar performance to its current top-of-the-line single-core CPU in single-threaded applications. This is in direct contrast to the 840, which runs single-threaded applications significantly slower than a 3.8GHz Pentium 4e.

The X2 4800+'s superb performance in single-threaded applications makes it much more flexible than the 840, which only really shines in a multithreaded environment. Arguably, it's this flexibility, and its killer game performance, that will make the X2 4800+ more attractive to enthusiasts.

The X2 4800+ is also expected to retail for significantly less than the 840 - £686 as opposed to £800. Both prices are undeniably extortionate, but the AMD processor is clearly better value. How it will compare with the Pentium D, which lacks Hyper-Threading but is likely to be significantly cheaper than the 840, remains to be seen, though.

Ultimately, both dual-core CPUs are ludicrously fast, but if it came down to a choice of one or the other for our next PC, we'd have to choose the Athlon 64 X2 4800+.

Author: James Gorbold

AMD Athlon 64 X2 4800+