If you are running a 64bit OS, then you can definitely see more than 4GB in the user space. A dual Opteron with 2x HDD, 1x PCI card and 8x memory DIMM will draw about 1.4A or about 336W in our environment. So you can pack in about 10 dual Opteron on a 16A power source. Regards LAI Loong-Fong On 19/7/04 9:18 PM, "Jeremy Mann" <jeremy@biochem.uthscsa.edu> wrote: > > I'm curious if there are people on this list that use dual Opterons for > their processing. We are in the process of trying to purchase several dual > Opterons to replace our aging P3 cluster and we have a few questions > regarding the upgrade. > > First, do you know if the opteron kernel will allow larger memory for user > space in 64bit mode that just 4 GB? We have two dual Xeon's with 4gb of > memory which we could never get more than 3.5 GB recognized by the 2.4 > kernel. > > Second, regrading power and heat, what steps have you taken to remedy the > heat generated by the Opterons and what kind of electrical upgrades have > you done? We have a VA Linux rack with about 20U's left which will house > the Opterons. It has 2 220 volt power rails (we only use one) that > delivers power to a 4U APC (I forget the model number) unit, a 4U quad > Xeon server, 2 switches and a 4U RAID array. > > Thanks for any suggestions you may provide. > > >