With the release of the Barton a couple months ago, a lot of people were anticipating great things with the L2 cache getting a bump up to 512KB. If you've been paying attention, you'll know that the performance was not all that dramatic over their previous Thoroughbred cores. Fact is, both are the same CPU except for the added cache. Both are 166FSB parts (the latter TBreds that is), based on a 0.13 micron copper fab process. Many had hoped for the jump to 200FSB, but that is only available with the more recent 3200+.

The Barton 2500+

Packaging is the same as the Thoroughbred, which means it's based on the OPGA, or organic pin grid array, packaging technology. The benefit over ceramics (used in the Thunderbirds) is two-fold as it lowers the impedance and the cost of the CPU.

As you can see above, the markings are for a 2500+ CPU. Despite the bump in Performance Rating, this CPU has a lower clock speed than the 2400+. The 2500+ runs at 11x166 (1.83GHz), whereas the 2400+ runs at 15x133 (2GHz). Those numbers are rounded up, but basically, the 2400+ is about 170MHz faster.

So why did AMD feel fit to add 100PR? Well, as we've seen with the P4 Northwood, the extra 256KB of cache they added (to go up to 512KB) made quite a difference in performance. According to tests in their labs, AMD is making similar claims that the extra cache merits an increase in PR. We'll be sure to prove or disprove these claims in our tests.

Overclocking

To be quite honest, I was originally quite anxious on what kind of overclocking success we'd have. We had a lot of positive results from our 2400+, and being at the bottom of the food chain for the Bartons, I was hoping for similar results this time around. Sadly, a lot of the overclocks I managed before were not attainable this time around. Here's what did and didn't work…

Out of the box, the Barton 2500+ is clocked at 11x166, which equals 1826MHz. The first thing I did was to jump to 12x166, which the CPU handled without any problems. Next up was 13x166, and this is where we experienced our first lockup. Upping the voltage on our Abit NF7-M to 1.85v added some stability, but after an hour or so of benchmarks, the system would freeze up again.

We pushed the vCore up to 1.9v and everything worked out fine. Keep in mind that we were using water cooling (courtesy of the Swiftech H20-8500), but a heavy duty air cooler such as a Swiftech MCX462+ or Thermalright SLK-800 and a huge fan will probably net similar results. At 14x166, our system would not boot, no matter what voltage was applied. 13.5 worked at 2.0v, but the system wouldn't run stable enough to do any testing. Increasing the voltage to 2.1v did not help at all. With the multiplier reaching the limit, it was time to start working on the FSB.

At the stock multiplier of 11, we got the FSB as high as 203. This was with our vCore at 1.9v. I did not run any benchmarks at this time, but the system seemed to be running fine. The FSB wouldn't go any higher at 2.0v, so we lowered the multiplier to 8. Surprisingly, I had even less success, with the multiplier topping off at 200. I went into Windows, and began messing around, only to find out that it'd crash whenever I started 3D Mark 2003. I went back to 11x203, and this time, I couldn't even get into Windows (!). I double checked our voltage, and yup, it was at a 1.9v vCore.

With that kick in the funsack figured out, I went for the highest CPU OC I could manage. It took some time figuring out the best multiplier and FSB settings, but in the end I settled on 12x200. The vCore is 1.95v, which is pretty much in the danger zone without the right cooling. Don't go trying this if you have a stock cooler.

So what are my thoughts on Ocing? Well, I know we had a little more success than some people, and less than others. Simply put, Ocing the Barton is a real crapshoot, depending on the CPU you get. I borrowed a friend's 2500+, and I couldn't get past 196FSB, no matter the multiplier and voltage. Another friend can do 13x210 at 2.1v, but he has a VapoChill setup. What bothers me is the Barton 2500+ wasn't as flexible as the TBred 2400+ in terms of OC options, and it certainly wasn't able to match the 2400+ in the maximum MHz OC department.

Test Setup

Abit NF7-M nForce 2: Athlon XP 2500+, 2 x 256MB Corsair PC3200 TWINX, Swiftech H20-8500, ATi AiW 9700 Pro, 120GB Western Digital SE 8MB Cache, Windows XP SP1, Catalyst 3.4.

Abit NF7-M nForce 2: Athlon XP 2400+, 2 x 256MB Corsair PC3200 TWINX, Swiftech H20-8500, ATi AiW 9700 Pro, 120GB Western Digital SE 8MB Cache, Windows XP SP1, Catalyst 3.4.

Test software will be:

SiSoft Sandra 2003
PC Mark 2002
PiFast
Unreal Tournament 2003 CPU Tests
Quake 3: Arena
Jedi Knight 2

The comparison CPU will be a TBred 2400+. Tests will be run with both CPUs at stock speeds to see if the extra 100PR points the 2500+ has over the 2400+ is deserving. We will also be running the 2500+ @ 15x133, to match the 2400+ clock speed. Finally, both CPUs will be evenly matched at 2GHz, running 12x166.

SiSoftware Sandra 2003

Although a synthetic benchmark, it's a popular one, freely available if you wish to make comparison benchmarks. We will be testing the CPU, and MMX speeds.

CPU Arithmetic Benchmark

CPU Multimedia Benchmark

It would appear that the extra 256KB of cache is giving the Barton a nice boost over the TBred. It isn't anything big though, but the improvement is there. Part of the reason is SiSoft is clock speed dependant, but it isn't enough for the 2400+ to catch up. This gap is more evident when we match the clock speeds, and we can see the Barton really pull away.

PC Mark 2002

As with the SiSoft scores, our PC Mark scores follow a similar trend. Nonetheless, the Barton does show that the extra 100PR is justified.

PiFast

A good indicator of real world CPU/Motherboard performance is PiFast version 4.2. We used a computation of 10000000 digits of Pi, Chudnovsky method, 1024 K FFT, and no disk memory.

Again, pretty close across the board. The Barton continues to lead the way, but the reality is, there is only a 2 second improvement on average, clock speeds being equal.

Unreal Tournament 2003

We used the scripts written by , which are excellent tools in testing various resolutions and detail levels. We selected the CPU test.

Here, things get a little clearer. Even at a lower clock speed, the 2500+ manages a 24fps improvement over the 2400+ at stock speeds, and a 17fps improvement when the 2400+ is pushed to a 166FSB.

Quake 3 Arena, 640x480 - Fastest

As with UT2003, we see similar performance scales with Quake 3. You'll notice here, as well as with the last and upcoming benchmarks that performance is best served with a faster bus.

Jedi Knight 2, 640x480 - Fastest

It's looking like the Barton is living up to its performance rating, and is showing the 2400+ that its time has past. JKII is a little more CPU dependent than Q3, and it shows here that the 2400+ is having some trouble keeping up.

OC Performance, 12x200

In order to reflect a little on what performance should be like with faster Bartons, I whipped up some OC results to add to the review. To keep things on an even scale, and to reinforce the previous results regarding PR and the extra cache, we OC'd both the 2400+ and 2500+.

CPU Arithmetic Benchmark

CPU Multimedia Benchmark

UT2003

Impressive numbers for sure, and the Barton shows that it's AMD's CPU of the future. Well, for the next few months anyways.

Final Words

Is the Barton an improvement over the TBred? Yes, it is. Despite the lower clock speed, the extra cache does give it an improvement over its older brother. Although we were using lower clocked models of both CPUs, the performance should scale accordingly between the two lines of CPUs as our overclocking tests have shown.

Is it a dramatic leap? In my opinion, not really. A few things did bother me about the Barton. For one thing, I would have liked to see some higher clock speeds right off the bat. I know the extra cache justifies the new PR, but this flip-flopping with clock speeds is going to end up confusing people if they start asking the sales people questions. I also realize that they made the jump to the 200FSB with the 3200+, but to separate their products clearly, I think the jump should have been made sooner.

Overclocking was a mixed bag. We did pretty well for the most part, but it seems that the Barton we have just didn't seem to like FSB speeds above 200. Considering our TBred didn't flinch at 230FSB and up, I was left a bit disappointed. Remember, this was all done with watercooling, and we used 68cfm fans on the radiator.

That being said, the Barton is a fine CPU. There's plenty of power to spare, and the pricing of the 2500+ is in the vicinity of the 2400+. Given that we did manage a stable 400MHz OC, unless you're the type who prefers running CPUs at stock speed, the 2500+ is the best choice for price and performance. Again, this is my opinion, but what do I know?

Pros: Good performance, low price point, 512KB cache.

Cons: Overclocking isn't as impressive as the TBred, lower clock speeds despite higher PR than earlier TBred CPUs.

Bottom Line: Despite coming off as somewhat negative in the conclusion, if you're running anything less than a TBred, the Barton should be on your list if an upgrade is planned. If you already have a TBred, hold on to it and wait for the Athlon64.

If you have any comments, be sure to hit us up in our forums.

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