Not sure, but I've played SRO on both a Dell D630 and E6400. The 630 had a 965 chipset and the E6400 has a G45 chipset and plays just fine with settings on medium.
A 915 is a pretty old chipset, if it's got 32 MB of shared graphics memory you might be able to.
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iSRO - AsparTame 8x - retired
Salvation - Aspar 70