CPU Upgrade Problem - GX260 A06

Question

Hello!  I've got a GX260 with an i845G motherboard.  I'm trying to replace the stock CPU (P4 1.8 SL66Q) with a Northwood 2.4 ( SL6WF).  I was using BIOS rev A09 but I downgraded to A06, as I've seen recommended by others in these boards.  When I put in the new CPU, the BIOS recognizes it but only runs it at 1.2 GHz.  Bus speed is 400 MHz.  I'm able to boot into Windows and run programs with no issues but CPUZ recognizes it as a 2.4GHz CPU running at 1.2GHz.    Is this CPU not supported or am I missing a step somewhere?  After installing the CPU, I reset the RTC via the jumper and I'm still getting the same result.  This also happened in both the A09 and A06 BIOS.   Any advice is appreciated.  Thank you!

Bobman101 · Answer

It sounds like the CPU is really an 800MHz FSB CPU. Becuase that chipset doesn't support CPUs with an 800MHz FSB, it clocks it down to 400MHz. Since the final speed of a CPU is determined by it's multiplier multiplied by the FSB, you're cutting the FSB in half, which explains the end result of 1.2GHz, which is half of 2.4GHz.

ejn63 · Answer

The other possibility is that it is a mobile CPU, which won't run at rated speed on a desktop board. What is the S-spec (code beginning with S inscribed onto the top of the CPU)?

vandalous · Answer

Thanks for the replies.  I think you nailed it on the head in that the CPU requires an 800MHz FSB.  Since the mobo runs at 400, it makes sense that it would run at half the rated speed of the CPU.   The CPU isn't mobile & the SL numbers are both in my initial post.

Locked Topics – Desktops General

CPU Upgrade Problem - GX260 A06

Was this post helpful?