AMD Athlon XP 1800

Reviewer: David Ross

Introduction
The movements in the CPU front over the past few years have been very substantial. AMD have changed from being "behind" Intel in core development and speed to overtaking them. Let's cast back to where Intel had the Celeron and P2 range of CPUs. AMD had the K62/3 range of CPUs. Lets be honest the AMD chips didn't cut it and as a power / performance beating platform the Intel Celeron architecture was far superior and also very cost effective. So at this stage AMD are loosing to Intel, but this is all to change and AMD manage to turn it around in a rather drastic way. They first of all launched the "Classic" Athlon which was based on the Slot A interface. This CPU was loved by all since it was cheap and very effective and the performance, well that was just mind blowing making many people decided to avoid the P3 route and go for the AMD alternative, which involved a new motherboard/CPU combo. But people were prepared to make the investment.

This platform matured quickly, and with this shift came a series of high performance chipsets, with VIA this gave AMD several options, they had the market in there grasp now. They decided that they should abuse this situation.

With a lot of effective marketing they needed people to adopt AMD platforms, many companies got behind them and decided to follow the route. They had the advantage that computer geeks loved the system and were more than happy to change to it but they needed to get some big OEMs behind them and get the corporations to adopt the new systems - this was something hard to change.

They then released the new wave of CPUS that involved an interface change to Socket A. Once they had this new platform in place there was nothing stopping them, apart from heat. Many people adopted the new platform, they got their new CPUs and motherboards, and were more than happy with this platform. Within this new breed of CPUs there was another new technology which was released to the market this involved a complete change in the way that memory operations worked, they moved to a platform which we know as DDR. This stands for Double Data Rate, for all of you whom have been in a hole for the past 6 months DDR is the following; basically normal memory reads on the peaks of the spectrum, with DDR it reads on the peaks and the troughs of the spectrum, this doesn't mean it is twice as fast (all the time anyway) but it is a performance increase.

With the release of these new CPUs they started a new range, the Duron range which was aimed at the budget user and was something which they released to compete with Intel's Celeron range of CPUs but instead it ended up in cases to compete with the Pentium 3 from Intel. This new CPU was basically the top end range but with less cache, with fast market adoption this made a big difference to the way that people chose thei systems.

Prior to the launch of DDR there was the release of the VIA KT133 chipset this was long awaited and it brought a lot more performance to the users. but with VIAs constant enforcement on the market they released the KT133A not long after which was more mature, and gave the users a lot more of an increase in stability and also in memory performance, something which the P4 had holding over the AMD line for a while due to the massive bandwidth of the Rambus platform. The CPUs kept running at the usual 50 MHz incrediments until in March AMD went a head with the DDR platform where they decided to launch the 1.33 on a 266 [DDR] Bus.

Later in the year they released the MP platform for dual CPU use, this was quickly adopted by the market and has taken off well. They then went ahead with the launch of the Mobile units which used less power, and also released a lot less heat to the local system. This was based on the new "Athlon 4, Palomino" or whatever you want to call it platform. So where are we today? Well the launch of the XP CPU from AMD which is another revolution in the market place.

The Athlon 1800XP CPU is a 1.53GHz clocked CPU but it has a new name, a PR name, this is basically the performance rating of the CPU, this processor is equivalent to an 1800 MHz Thunderbird based core. This if you ask me is pretty damn quick! There are a lot of enhancements which AMD have made to this new core. The first thing which you will notice with this CPU is that the "holder" for the core - the part which used to be a purple ceramic colour is now a brownish colour the reason for this is that AMD have now made this out of an organic matter, this is a lighter and also seems a lot thinner. Will we see an organic matter based Duron soon? We can only wait and see.

The key new factors with this new core are what AMD calls Quantispeed. Some people think that Quantispeed is just the name for the new processor rating system, however it covers a whole list of new features on this Thunderbird/Duron evolution of their 7th generation x86 core.

First up we have enhancements to the processor pipeline giving the new core a slightly higher IPC than TBird/Duron and allowing it to do more work for a given clock speed.

Next up we see AMD touting the floating point unit of their core and with good reason. AMD deserve much praise for the FPU unit in this processor family and it's the quickest ever x86 FPU unit in any processor.

The 3rd part of Quantispeed is the data prefetch unit in the new core. The CPU is intelligent enough to make a very educated guess at the next block of data that the CPU will be working on. It prefetches it into L1 before the instruction operates on it meaning that the data is there automatically and it doesn't have to waste cycles getting the memory after the instruction is already in the pipeline. Sometimes it'll guess wrongly and the data wont be in L1 meaning a possible trip out to system memory or even disk, but the CPU has a low miss rate and overall performance increases.

The fourth and final part of Quantispeed is modifications to the Transition Lookaside Buffers, part of the L1 and L2 cache arrangement. The buffers hold information about the data held in memory. In CPU's that implement Quantispeed, the buffers are larger and exclusive between L1 and L2 caches, meaning that the TLB buffer in L2 doesn't mirror the L1 TLB. This helps reduce cache misses and means the CPU has access to the correct data quicker and for more of the time, improving performance.

All in all the Quantispeed enhancements to the core add up to a healthy performance increase and allow AMD to legitimately use their new performance rating and rate a 1533MHz CPU that uses Quantispeed as fast as a 1800MHz Thunderbird CPU. While this may or may not be entirely accurate since an 1800MHz Thunderbird running at 10 x 180 should give superior performance to a stock clocked 1800XP, the rule holds quite well.

When I first got the unit I decided to do some serious testing, I had been playing with the 2 GHz P4 which we had in the test lab, and we were impressed with the new format and speed (Ed. the review should be up soon!). As this is "only" a 1.53 in essence we wondered how it would perform against other platforms, what I can say... so far we are very impressed. The CPU itself is the same as any other socket A CPU, you plug it in and you put your heatsink on and run it. Simple really. ;)

Test Platform
We decided to upgrade our main AMD test system, to the new VIA based KT266A motherboard. The advantage of us doing this is that we can see what YOU can get when this board finally hits the shelves. We have to say if you are planning to upgrade soon do not buy a new motherboard until this one hits the shelves. This chipset we have to say is now one of our favorites, it is a lot faster than the predecessor and it has other enhancements such as the higher memory bandwidth and also the increased stability meaning this is a chipset to watch. Our board was the EPoX 8KHA+ which should hit the stores in quantity in around 2 weeks. We have also adopted the Abit range of graphics card as our main testing card as it is the latest version of the Geforce 3 out, and it performs up there with the Ti range. We will be moving to the Ti range when we can get a set of the cards [so we can all run them.]. This standardization is showing you guys what you can buy and use on the market, we aren't going to go out and use kit which you can't get as the figures to be honest will just be rubbish. We have also taken the move to standardize on Crucial memory, based on the Micron chips. This memory is the best memory in the world in our eyes, we haven't had any of these come to us faulty, or even heard anyone who has had any problems with this memory. So there's that lot sorted now on to the testing.

From the moment I installed this CPU in to the test system I was expecting a lot. I had heard all the chat from AMD about its power and speed, but I wanted to check this out for myself. I built the system, and decided to install Windows XP on it; this meant that we would be using the latest of everything in our labs. I installed XP in the same usual way that we do, and rebooted, the system booted to the desktop in under 15 seconds from post, this is VERY impressive, I know it isn't a *real* benchmark, but first impressions count.

For the initial review of this product we are going to do a comparison of the P4 2Ghz, 1800XP CPU, and the 1Ghz Morgan Duron, all of the TOP end CPUs which you can get on the market at the moment. The 1800 and the 1Ghz will be tested on the DDR KT266A platform, and the 2Ghz P4 will be tested on an Abit TH7 II with Rambus. Everything else will be kept constant bar the motherboard/CPU combo.

You can find Benchmark Results and the rest of this review by clicking here.

The entire review is (c) hexus.net 2001 and is published with its permission.