Original URL: http://www.theregister.co.uk/2005/08/12/review_amd_x2_3800plus/

AMD Athlon X2 3800+ dual-core CPU

Entry-level two-core champion?

By Trusted Reviews

Posted in Reviews, 12th August 2005 15:51 GMT

Review At the beginning of the month AMD launched its latest budget processor, the Sempron 3400+. Launched on the same day was the dual-core Athlon 64 X2 3800+. Right now you have the choice between single core or dual-core but before long dual-core will become very much the norm, writes Benny Har-Even.

AMD Athlon X2 3800+It's easy to understand why. They say that two heads are better than one, and eventually all applications will be coded specifically to make the best use of both processor cores. But as this conversation with Half-Life 2 developer Gabe Newell shows, it may be some time before games reap the benefits. Either way, dual-core is still a good thing as one processor can sit doing boring stuff like running anti-virus, anti-spyware and firewall software as well as other housekeeping tasks, while the other does more important things, such as delivering super-realistic physics in the latest first-person shooter.

The problem is that two cores in a chip makes for a more complicated and therefore more expensive processor. The top of the range X2 is currently the 4800+. This sports a 2.4GHz clock and 2MB of Level 2 cache shared between each core. That's a lot of transistors. And more cache means, well, more cash, and the Athlon X2 4800+ will set you back £630 at Komplett. It may be the gamer's choice, but only if they've been given one or won the lottery that week.

Even the 4200+ with a clock of 2.2GHz and two 512KB caches costs £350, making the X2 range generally more expensive than Intel's dual-core Pentium D. To combat this AMD has launched the X2 3800+. The naming convention may not have that magical 4000 figure but it's still got it going on. It hits 2GHz on the nose and has 512KB of L2 cache for each core.

The 3800+ actually differs from the previous 'Toledo' X2 in that it's based on what AMD internally calls the 'Manchester' core. This means that it's been designed from the ground up to have only 512KB of cache. With less cache and a lower clock on a 90nm Silicon-on-Insulator manufacturing process, the die size is down to 147mm² with 154m transistors, compared to 199mm² and 233.2m transistors on the 4800+. That makes it a lot easier to produce in high quantities, which helps keep the costs down. It also brings down the maximum thermal power rating down to 89W compared to the 4800+'s 110W. In terms of power consumption and thermal output, that's a lot more friendly for any PC, be it at home or work. It also suggests that there's some headroom for overclocking.

Then of course there's the price. The 3800+, boxed with fan, costs £260 from Komplett, while the next X2 up, the 4200+ costs £350 that's £90 for the extra 200MHz. The closest Intel CPU to compare it to in terms of price would be a Pentium D 830, a 3.2GHz CPU costs £235. However, Intel was not able to supply us with one, so instead we could only use our previously tested Pentium D 820, a 2.8GHz CPU, to compare the X2 3800+ with. This costs £175 from Komplett but even so, the 820 has a clock speed advantage over the X2 3800+ and double the L2 cache.

To test the X2 3800+ we used an Abit A8N Ultra, with 1GB of memory and a GeForce 6800GT graphics card. On our review sample we obtained from AMD, I noticed that among the codes on it were the initials BHE, which also happen to be my initials. Well, they say that somewhere out there, there's a CPU with your name on it, and I appear to have found mine.

AMD Athlon X2 3800+ SysMark

AMD Athlon X2 3800+ POV-Ray

As you'd expect, given the price difference, the X2 3800+ outpaced the Pentium D 820 in SYSmark 2004 with a score of 220 compared to 202. In PC Mark 04 it also beat the 820, scoring 5783 to 5488. Interestingly, it lost out to the Intel chip in the individual CPU test and the graphics test - obviously the extra cache on the 820 was making itself felt there.

In POV-Ray - an application that can really take advantage of dual-core - the X2 3800+ is faster than the 820 in both single- and dual-core modes. However, while the Intel chip was almost exactly twice as fast in dual-core mode as it was in single-core mode, the AMD chip was slightly less than twice as fast. All in all, though, the X2 2800+ is the clear winner.

One thing that that some might wish to try is overclocking. Having a quick look in the BIOS reveals that the multiplier on the CPU is locked. This means that overclocking has to be done by raising the bus speed and adjusting voltages for CPU and memory to cope.

AMD Athlon X2 3800+ PCMark 04

AMD Athlon X2 3800+ PCMark 05

Finally, I also did some subjective testing, running multiple applications at the same time, to get a sense of how the X2 3800+ dual-core feels in real-world usage. One big advantage I noticed was the ability to switch out of a game back to the Windows desktop much more smoothly. It's often necessary to do so to adjust some settings in Windows and the ability to do it less painfully is a welcome bonus.

Verdict

If you've been tempted by the prospect of dual-core but have been put off by the price the X2 3800+ is the CPU that should make you reconsider. It's still about £85 more than Intel's entry-level chip but the extra performance is definitely there.

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AMD Athlon X2 3800+
 
Rating 80%
Price £276
 
More info The AMD site