Older diminsion 2400 upgrading to 3.06ghz pentium 4 ht

I took a look at the manual and it in no way indicates that hyperthreading is an option with this mainboard. As for the latest bios it seems Dell has not decided to support this cpu with a bios update. Try loading a program called CPU-Z and see what it indicates for your cpu. It could be the bios is not recognising it but it is still performing as a 3.06...

Thanks for the reply here's an exert from the manual also the data sheet says it supports this processor

page 17

Hyper-Threading
NOTE: Hyper-Threading is supported only on computers that have 3.06-GHz (or higher) microprocessors
installed.
Hyper-Threading is an Intel® technology that can enhance overall computer performance by
allowing one physical microprocessor to function as two logical microprocessors, capable of
performing certain tasks simultaneously. It is recommended that you use the Microsoft®
Windows® XP operating system because Windows XP is optimized to take advantage of Hyper-
Threading technology. While many programs can benefit from Hyper-Threading, some programs
have not been optimized for Hyper-Threading and may require an update from the software
manufacturer. Contact the software manufacturer for updates and information about using Hyper-
Threading with your software.
To determine if your computer is using Hyper-Threading

Link to supported processors

http://support.dell.com/support/edocs/systems/dim2400/en/sm_en/specs.htm

luttrell

The 2400 supports Hyper Threading,  to enable Hyper-Threading, go to the 'CPU Information' section, see HERE 

The 2400 can use either 400MHz or 533MHz, Socket 478, P-4 processors with a 512kb or smaller cache and cannot use any Prescott processors [1mb cache].

Is the processor you installed, a Northwood [512kb cache] and 533MHz FSB?

Bev.

yes it's a northwood 512kb cache 533mhz reported by cpuz.  In the bios it does not have hyperthreading enable option but does have a compatible/normal option for the cpu - bios version a05.  I might try reflashing the bios next. 

Did you check the number of the processor on the Intel site?  Your report looks a lot like an 800 MHz FSB processor being run at 400 MHz.

double checked the processor and it's a mobile with the multiplier stuck at 12 not 24.  Will get correct processor

Thanks for you time....