The Secret Of The Multiplier
The multiplier expresses the ratio between the processor clock speed and the FSB clock. For the Pentium D 805, the combination of FSB and processor clocks results in a multiplier value of 20x. By comparison with other CPUs with 200 MHz or 266 MHz FSB, this is a very high value - 12x and 14x are much more common. But this also makes the Pentium D 805 a good candidate for overclocking. Simply by raising the FSB clock rate to 200 MHz, the resulting CPU clock rate rises to 4.0 GHz once the 20x multiplier is applied (20x times 200 MHz equals 4.0 GHz).
You can peruse a list of all currently used multiplier values in our Intel Desktop Processor Overview chart.
An overview of all Intel CPUs back to the Socket 5 era (1993).
By default, the top-of-the-line Extreme Edition 965 uses a multiplier of 14x.
The multiplier for the Extreme Edition 965 can be set in the BIOS anywhere from 12x to 60x, but such capability comes at a high price. This CPU costs around $1,100, which few users can afford to spend just on one component. This is yet another reason why those who buy a high-end CPU should also consider investing the time and effort involved in overclocking.
The 20x multiplier is burned into the CPU and may not be altered using a special BIOS, nor with a hardware jumper on the motherboard.
Since the D 805's multiplier is fixed, there's only one way to overclock it: by increasing the clock speed for the front side bus.
Current page: The Secret Of The MultiplierPrev Page Inside the Pentium D 805 Next Page 133 MHz FSB: Perfect For Overclocking
Stay on the Cutting Edge
Join the experts who read Tom's Hardware for the inside track on enthusiast PC tech news — and have for over 25 years. We'll send breaking news and in-depth reviews of CPUs, GPUs, AI, maker hardware and more straight to your inbox.
Tom's Hardware's dedicated news crew consists of both freelancers and staff with decades of experience reporting on the latest developments in CPUs, GPUs, super computing, Raspberry Pis and more.
I am quite interested in your post regarding the D 805. Considering that it is now available for around $60.00 (03/20/09), it still sounds like a steal. We just upgraded our Adobe CS2 software to the new CS4 Master Suite, which caused the need for a graphics card upgrade. We have an nVidia GeForce GTX 260, but haven't installed it because our computer is a HP Media Center PCm7350n computers each with a 2.8 GHz CPU on a ASUS P5LP-LE mobo. Your article seemed to imply that there is software available that might adjust the clock from inside windows and we are wondering if it can on that mobo or if we will have to get a different mobo. If so, we are wondering what might be our most cost effective but stable options. We are certainly going to need a new power supply for the GTX 260, which requires 525 Watts. We are looking at just putting in PC Power & Cooling’s, Silencer 610 EPS12V power supplyand letting it go at that, but we are also thinking about upgrading the CPU and mobo if necessary.Reply
Of course, we would like to keep the cost down as much as possible.
We have no idea where the best bang for the buck will be. For us a stable system is more important than blazing speed. Thus, the HP's worked fine for what we originally got them for; it’s just that our graphics and video production software are forcing upgrades in speed and power.
The D850 chip sounds incredible and the power supply we already have to get will handle overclocking that chip. It even sounds like that chip will work in the existing mobo if we can find a way to change the clock speed from inside windows instead of from the BIOS. HP BIOS does not allow adjusting the clock speed in the BIOS but can't BIOS just be changed as well; isn't it just an EPROM?
Anyway, even if we opt for changing out the mobo for another case compatible Asus mobo, we still have to answer the question of which board and chip combination will give us the most stable service for the least cost.
Any ideas that might help us plan the most appropriate upgrade and the least cost?
TniasAny ideas that might help us plan the most appropriate upgrade and the least cost?Reply
With the price of components that you need to make this run stable, and the amount of electricity that this would use, a cheap Core 2 and motherboard and DDR2 memory would cost you less in the long run.
Intel Pentium Dual Core E5200
Kingston DDR2 2x2GB 800MHz
This should cost less than $200.
4 year old thread!Reply
11206355 said:4 year old thread!
no hate pl0x