Thanks for your reply, I have to go back on what I said.
The thing is that I've used W3 while I was being hit by a huge amount of traffic. The server at that time was already at 20% or so, with W3 the server load went to unimaginable numbers like 300%. The server just couldn't handle. So what I did was stop the server account completly, and server load dropped almost down to 0%. Then I restart it with W3, and since then what I've heard has been true. It does a good joob indeed, altough I still have some server load that I wanted to get decreased. And I do think that W3 can do that job.
So these are some of the issues that I want you to clarify if possible:
1) I've seen that emptying cache on server peek hours might be self-suicide, I did it and it went to 500% (no j/k, it really happened), so I think that it was my fault there, or am I wrong? We can empty cache whenever and we wont notice server loads?
2) Another thing is that since my site has something like 100,000 views/ days is pretty possible that when pages are cached or re-cached they start caching and auto-cleaning at the same time. It means that with 5,000 users online is pretty possible that we have 25% of the website caching and cleaning at the same time, what equals again to huge server load. I mean if cache for page A, B, C and D starts at 1pm, they will also be cleaned and re-cached at the same time, right? Or are there different expire times for each visitor?
3) For dedicated servers do you recommend the opcode option? Or you always recommend disk (enhanced)? I'm asking this because I'm thinking on moving this website to a dedicated machine (Quad Core Xeon® X3460 Processor,4 x 2.8 GHz HyperThreaded Cores,8 MB L3 Cache, 1333 MHz FSB,16 GB 1333MHz DDR3 Memory,Serial ATA Storage in RAID 1) so the default settings are also the same for this kind of dedicated?
4) Since DB is my main issue, do you suggest an higher number than 180 for Maximum lifetime of cache objects and more than 3600 for Garbage collection interval (both in the dedicated)?
Sorry for the multiple questions, but now that I'm really digging W3 I want to know how to take the most out of it. Thanks alot!