What I have now:
Front end: Dual Xeon HT 2.66s, 3 gig of ram. SATA HD.
Back end: Dual Opteron 244's, 3 gig of ram, SCSI HD's
My forum avg's around 1400 - 1700 users online (15min timeout), about 1/3rd only see the archive, the rest are active on the forum.
For $100 a month less, I can get:
Quad AMD Opteron 852's (4 cpus each running at 2.6ghz)
8 GB Memory (upto 32 GB)
4x 36gb 10k rpm SCSI hdds
I really like the idea of managing one server, not two. Too many headaches for me lately. Think I can pull off running a site of my size on this single server?
Dam What Forum Do You Own?
I would go with the Quad AMD Opteron 852's w/8gig memory and the SCSI 10k drives.. I'd go RAID 10 on it though and use a good RAID card if that is an option. Also 15k RPM drives but doesn't have to have them.
I went from Dual Xeon Servers (2x) to one 2x Opteron 270 server with 15k SAS drives and it completely smokes using separate servers for me. I'd say that Quad Opteron 852 server should be better than the set you are currently using.
I would go with 2 servers myself - splitting db and web is always better than it all on the one server, unless the 2 servers are much less powerful.
2 servers aare almost always better than 1, the more the marrier.
Unless you don't need two of them, or the two are not nearly as powerful as the single physical server. You can also save money with using one physical vs two (again, depends on spec's) and if you need two or more you can always add more later.
Two servers for shure. Split the database and the http. And if one server get screwed for X reason, you could transfer on one for a small amount of time (and put a maximum connected user limit). I would go with two servers!