Which is better? I have a MSI MS-6577 motherboard with FSB 400/533 & Socket 478, so these CPU's are my best options. Does the Hyper-Threading technology of the Pentium 3.06 really increase performance past the 3.20 GHz rating of the non Hyper-Threaded Celeron? Also, I understand that you need to reinstall Windows when you swap motherboards, but my Windows XP was factory installed on a partition of the factory hard drive and I don't think I can access it, unless I am doing a system restore and that won't help with a mobo swap. Is there a way I can upgrade my mobo without buying another Windows XP? Here are some specs for a comparison on both CPU's: Intel® Pentium® 4 Processors 3.06 GHz sSpec Number: SL6S5 CPU Speed: 3.06 GHz PCG: Bus Speed: 533 MHz Bus/Core Ratio: 23 L2 Cache Size: 512 KB L2 Cache Speed: 3.06 GHz Package Type: 478 pin Manufacturing Technology: 0.13 micron Core Stepping: C1 CPUID String: 0F27h Thermal Design Power: 81.8W Thermal Specification: 69°C VID Voltage Range: Supported Features: Hyper-Threading Technology Intel® Celeron® Processor Family 3.20 GHz sSpec Number: SL7NY CPU Speed: 3.20 GHz PCG: Bus Speed: 533 MHz Bus/Core Ratio: 24 L2 Cache Size: 256 KB L2 Cache Speed: 3.2 GHz Package Type: 478 pin Manufacturing Technology: 90 nm Core Stepping: E0 CPUID String: 0F41h Thermal Design Power: 73W Thermal Specification: 67°C VID Voltage Range: 1.25V-1.4V Thanks to all who read this.