Wow...

Couldn't say about flash, probably using it im not sure...

Next time I'm on OSX I'll monitor the CPU usage with Activity Monitor, and see whats happening etc.

Specs (taken from InsanelyMac sig):
Board: ASUS A8N-E (nForce 4 Ultra)
CPU: AMD Athlon 64 3700+ Socket 939 2.2GHz
Graphics: ATI Radeon X1600 Pro 256MB PCI-E
Memory: 1GB DDR 400 RAM (2x 512MB - Dual Channel)
HDD: Seagate 300GB SATA

Its a TARGA Ultra AN64II 3700+ PC, so couldn't say on the cooler or thermal paste, since its not built by me. Also I doubt its overclocked. Cool'N'Quiet is activated but is it supported by OSX? (I've got the 9.2.0 ToH kernel and the 9.3.0 modbin kernel)

Leopard Install: Leo4Allv3 (Kernel 9.2.0, Old NForce, AC97, forcedeth-v, Zydas USB, About This Mac, rest unchecked), updated to 10.5.3 using Combo update (netkas method), restored old AppleACPIPlatform.kext, AppleSMBIOS.kext, System.kext, installed kernel 9.3.0 (copied the mach_kernel to /), and patched using 10.5.3 decrypts.

Btw, on Windows, my CPU is currently at 45° C (monitored using PC Wizard 2008)

When checking the temp after OSX I quickly reboot into the BIOS (its fairly fast), at this point its usually 57°C, booting up windows, it doesnt take long for the temp to cool down to the 40's.