X4 Ray Tracing - Optimal CPU

[Ian Pellant]

marty,

It depends on the processor and the motherboard vendor.

My old box is a "Shuttle" - over the years I've built 3 others based on AMD... mine is an Intel P4 660 3.6GHz. Shuttle provide what they call "XPC Tools" - a software utility for monitoring the system (temperatures, fan speed, etc) and overclocking. It makes it easy to experiment with overclcoking. If the system locks, a reboot will clear the settings. Quit XPC Tools and the system is back to normal. My old box overclocks to just under 4GHz by bumping the FSB from 200 up to 220. Ray tracing improvement seems in a linear relationship with the system speed.

Intel tend to discourage overclocking for a few commercial reasons as well as technical. It was fuin to run the Intel Processor ID utility (can find it on the Intel web site) and see the big red warning that the system was overclocked.

The AMD FX-8nnn series processors black edition are "unlocked" to almost encourage overclocking. The Asrock motherboards come with Turbo Boost utilities to allow overclocking. The nominal bump top speed of the FX-8150 is 4.2 GHz. It can easily be boosted to 5GHz on air cooling; perhaps more. WIth liquid cooling, it should be able to run happily at 5.5GHz.

If your motherboard manufacturer did not provide software tools for overclocking, then it can be done manually by entering the BIOS at boot time and setting the core cpu speed or voltage, the FSB (Front Side Bus) speed and the memory speed or voltage. If you get it wrong the system won't boot.... that is why systems intended for enthusiasts will have "system reset" button somewhere in a recessed hole on the back of the computer... without that, using the BIOS clear jumper on the motherboard to clear the settings (or remove the 2032 battery for a few minutes).

If you web search you may find an article specific to your CPU and motherboard.

If you have a run of the mill, brand name system, then the manufacturer has probably tried to discourage overclocking... it will "void the warranty".

I like Shuttles because they are compact and very cost effective. Also means the case, motherboard and power supply are all warranteed by the same company and they do proide overclock tools. (see www.shuttle.com). Shuttle will cost about Aus $1400 for an i7 2600 with CPU, memory, hard drive, optical drive, Win 7 Pro. They do not have a box for the AMD FX-8150... which is a big hint that they are not favouring AMD this year. It will be my i7 choice.

Cheers.