So to answer the questions. I am using MSI Afterburner to do the overclocking and I do have the unofficial OC enabled.
The Brand is Sapphire and the model I believe is 100297-2L Let me know if that doesn't make sense. (this one does vent into the case)
VGA SAPPHIRE|100297-2L HD5830 1G
same as I have.. above is the part number from my newegg invoice.
mine is in a dedicated mining rig with XP Pro so cant comment on aero with low mem clocks. I use trixx for overclocking. PSU is an Antec Basiq 500. not a high end PSU by any means, just a decent no nonsense one. using GUIMiner with "-v -w 256 -f 5" flags