The first one there is a server board with the option of a second cpu while the second looks like it could easily be a Socket A model due to the zero insertion type socket and retaining lever. On many old boards the battery was either a different shape and type or the cmos was maintained by a charge held in a capacitor on the board itself. Desktop boards at this time pretty much use the 2032 numbered lithium battery whether DL or CR depending on brand. Duracell would be DL while Eveready Energizer would be CR.
On the older boards there you also have to look at what support can still be found as far as the main drivers needed and what cpus can be found from a site like EBay. Or you simply grab from another older beater case that no one has any use for with a working cpu of that type inless you already one onhand.
On odd thing came about when reassembling an old Socket A build here where the cpu was thought to have been done in by overheating and the fsb had to be lowered to see an XP3200+ run as an XP2500+ at 166 in the bios instead of 200mhz(200x2=400mhz). Suddenly it started running at 200 again and as normal as ever after sitting around for quite some time. Tuff old AMD cpu there!
