CPU Upgrade guide

Intel

Pentium 4
The Pentium 4 was a big step for Intel. Rather than sticking to the same design as before, they increased the pipeline on the basis that they could rapidly increase speed to compensate. This caused much confusion for people that compared the Athlon and earlier Pentium designs, forcing AMD to create speed ratings and inform people on the "Mhz myth" so that they did not lose out.
The Pentium 4 is a high performance chip, particularly in memory where it is almost twice as quick as Athlon xps. However, it needs this to fuel its long pipeline - without it its performance drops considerably. The transitions to 133 and 200fsb caused big rises in performance, and the addition of hyperthreading technology improved multitasking no end. Intel quote a bus speed 4 times the FSB due to its quad pumped design, but this is inaccurate since it is only internal of the chip itself.
For discussion of chipset designs, check out the Intel motherboard guide.
First Socket: 423 core
The first Pentium 4s came out on the 423pin socket. This was a transitional period and alienated many customers since they needed to buy a new board to use the later chips. Speeds were low and the new design confused many customers.

The next core: Northwood on 478pin
The Northwood was the first 0.13 micron design, and gave Intel the ability to ramp the speed up considerably as well as reduce the voltage required. The movement to 133 bus speed improved performance yet again. This design scaled all the way to 3.06Ghz. A later version of the core (called C) started at 2.4 and scaled to 3.2. This runs on a 200 bus - greatly increasing performance above the 133 bus designs. A new technology called Hyperthreading was added - this allows the processor to work on more tasks at the same time more effectively. This results in smoother operation with many processes going on at the same time, but puts more strain on the chip and other parts of a system.

Expensive but powerful - the Extreme Edition
To try and combat the thirst for memory bandwidth and reduce the starvation of the chip for information, Intel added some extra cache memory - 3Mb - to the chip directly resulting in the extreme edition. Though more powerful and compares well to the new AMD chips, it is hideously overpriced and hard to find. Strictly one for people with more money than sense.

The new core - the Prescott
The Prescott is a brand new design for the next generation of the Pentium series, but keeps the same name (plus an E). The first of a new breed of technologies, it should scale superbly. On the 478 pin design, it will only come in up to 3.4Ghz and no further. IT is as powerful as the Northwood core (just) but has many underlying changes for better multitasking and future enhancements. The major problem is its requirement for power and cooling - much more than the older core. Most motherboards will not be able to handle the 3.4 properly, and the heat it puts out is ridiculous. Again, it is overpriced and hard to find - avoid it for now until they address the many problems.
The new socket is also troublesome since the only chipsets available so far need an entirely new system - memory, graphics card and PCI cards all will need replacing.

Celeron
Intel have kept the Celeron name alive. With half the cache and limited to the 133 bus it destroys performance of the memory hungry core design. Otherwise, it is much the same as the Pentium 4 with lower prices, but is pointless as a purchase compared to the cheap and powerful AMD choice.
The newer prescott core based version is better due to the improvements and extra cache, but the duron can still outstrip it. Since the athlon XP range will be replacing the Duron, Celeron will soon have no place in the market.


The future
Intel is on the edge of a new socket and a further die-shrink to 0.09Micron which should solve Prescott's problems. Later chips are on their way - "Tejas" will be multi-core, supporting more than one processor in the same socket, and x86-64 will be added to later versions of Prescott.

AMD

Athlon XP
Unlike Intel, AMD have stuck to the same socket as their Pentium 3 alternative, the original Athlon. Various enhancements were added to the older core, resulting in cooler running, lower voltages and better performance. Due to the lower performance per Mhz of the Pentium 4, AMD moved to a performance rating so that they could compare more directly. This was adjusted to changes in cache and bus speed.
The Athlon XP is not quite as quick in memory operation as the Pentium 4, but due to the more traditional design it does not require it as much. A single channel DDR system is easily enough. Aside from processing speed and bus speed increases, the only changes have been to cache size. AMD quote a DDR bus which is twice the FSB.
For discussion of chipset designs, check out the AMD motherboard guide.

The first core - the Palomino
The Palomino was based on the 0.18Micron design, like the original Pentium 4. Unlike Intels, it scaled pretty well which helped AMD with the later introduction of the 0.13Micron chips. It ran on the 133 bus only and always had the same 256K of cache. Speeds were from 1.4 to 1.7Ghz (xp1600 to xp2100).

The Die shrink - the Thoroughbred
Once AMD got their shrink sorted, they released the new core. With lower voltage and thermal properties, it allowed them to scale even further as well as replace the older cores with cooler ones. Later chips (2G/xp2400+ and further) moved to the 166bus and allowed even more performance through this increase.

More performance: the Barton
To improve matters further, AMD doubled the cache to 512. This resulted in marginally better thermal properties due to the large core size, but mainly just improved performance. Bartons are not named differently, but are available as xp2500, 2800, 3000 and the 200fsb 3200. There are two versions of the 2800 - one isn't Barton but has a higher speed.
Later chips that would be Tbred are actually cut down versions of the Barton to save production costs much like Pentium/Celeron and Athlon/Duron. Named Thorton, it is essentially the same as Tbred. It seems to be better for heat output due to the larger surface for cooling and therefore better to overclock.

Duron
Like Intel, AMD have kept the budget name. Based on two cores - below 1.3G it is a cut down version of the older Athlon, above it is the Morgon core which is a cut down version of the Palomino. Some ones also come on 0.13micron, but information is scarce. Like Celerons, these are mainstream chips with some cache removed to save reject costs. They outstrip Celerons in performance since they are not limited by their memory bandwidth at all. For severe budgets, you can't do better than a Duron.

Athlon 64, socket 754
The new core is a brand new design, socket 754 and even chipset design. It uses a new process for production that severely improves thermal properties and power requirements, helping it run cooler and better. One huge change is that the memory controller is actually built into the chip, resulting in very high performance memory operation that Intel would die for. This makes it outstrip XPs on lesser clock speeds. One other addition for the future is 64 bit operation - this will result in more performance once it is supported by software. They have therefore kept the older rating system, with 2Ghz 3200+ and 2.2Ghz 3400+. There is also more reasonable priced 3000+ and 2800+. They are still pretty costly, but prices will go down.

FX/A64 series, socket 939
Based on the same core design as the 754 pin, but with a dual channel memory controller instead of the single channel in the 754 pin. The transition FX with 940 pins and expensive memory has been replaced with the normal memory-using 939 pin. The FX does not use the rating system but a numbering system to separate these higher performance ones from the mainstream series. The speed rated a64 versions have half the cache of the bigger FXs. It has a good deal more performance - compares well with the Pentium 4 EE chips. There is the cost, which is a very large at the moment, though not quite as much as the P4 EE.

Sempron
The new sempron chips are design to replace the duron of the old system. They are currently the same as athlon xps, but eventually they will move to a 754pin a64, but minus the x86-64 instructions. This will provide a big jump in performance and outstrip celeron by a silly amount. There is even talk of a dual channel 939 pin varient.

The future
Further speed increases are expected, and sempron will move to a A64 core by next year. Multicore processor are also being designed.

Conclusion

If you are running a fast Pentium 4 or Athlon XP, stick with it for now. There is little point in moving to either a Prescott or an Athlon 64 due to high costs, changes in chipsets and small increases in performance. If you must have latest technologies, then go for an FX or A64 - the future prospects are best on this platform, especially the 939pin line.
If you don't need latest tech and want a new computer, then I would go for a mid range Pentium4 200 fsb with hyperthreading. The difference in floating-point and memory performance over the XPs is worth it. Value wise, you can't go wrong with an XP though, just don't go above the 2800 speed - the extra price per MHz is huge.
Last modified: 01/06/2005Newer