a note on perspective - regarding the integrated GPUs - HD 6290 vs HD 6250
neither are double precison - single precision only and slow-at-that due to the low power input
both of them are very low-end, say relative to a HD 5770 (Juniper) 1024MB DDR5 PCI-E 2.0 (far below a HD5770 in fact)

The G-series appears to be restricted to a 'soldered' 1GB DDR3 SDRAM
whereas the C-60 will take upto 16 GB DDR3 RAM (2 x 8GB DDR3)

Wwhen calculating the performance for the dollar things get very muddy very quickly.
The G-T40E is meant to be low on power requirement and achieves that with 1GB RAM (at much cost)

But consider the ASUS C60M1-I includes the mobo, 1GHz (Turbo to 1333MHx) CPU and integrated GPU for $78
Stack a few of those and they become very quickly viable as CPU crunchers (Beowolf or LTSP Cluster)
esp. considering the low TDP
but the blessed thing has a PCIe 2.0 x16 slot

I have the RAM available and the GPUs (x 3) available to slot into these and fire up
As a cruncher this ASUS kit is set to go.

Want to build a LTSP cluster on the cheap?
I think Dirk found us the kicker candidate.
Yup.