As a VPS user myself, I have been trying different service providers with mixed results. Over the past few weeks, I've noticed something that I'm pretty sure some people never thought about.
When you buy a VPS from a vendor, they will say that you get your own resources fully allocated but in fact there's one very important point that they know is not true and they won't want to mention it to you or in public.
For example, if you buy a VPS with the following specs: Core i7 3.7ghz, 4GB ram and 50GB SSD hard drive, on paper it looks alright, right? Yes you will get fully allocated 4GB ram and 50GB SSD space, no question about it. But what about the one most important thing here, the CPU itself? Exactly ! It's being shared with some other people !
So a VPS vendor could simply buy a dedicated server with these specs: Core i7 3.7ghz, 24GB ram and 300GB SSD drive. Then they can come up with the aforementioned package selling it to SIX different people. These 6 people will get equally 4GB ram and 50GB SSD space. BUT they will be sharing the same CPU chip !
So however powerful the CPU may appear on paper, if it's being shared with multiple people running many different things on their respective VPSs, it will slow down, regardless of the CPU's speed, cores and threads. Just imagine if these 6 people are running just SER and CB at the same time and they use 300 threads each. That's already 1,800 threads altogether. Never mind all the other software they might also be running in the background.
Some VPS vendors might tell you if you ask them how many people are on the same node as you. They might say 2-3 people but how can you know for sure? How can you know they're being truthful ?
If you don't believe my theory, you can try what I did to confirm it's true. When SER first slowed down on my VPS for no reason even after I restarted it and Windows, I stopped it and tried running it on my average-specced home PC instead. And mark my words, it was running even faster here. So how can this be possible? I mean my home PC has nowhere near the specs of the VPS but it runs SER and CB faster? Simple, it's because it's a standalone system that's not being shared with other people. I'm mainly talking about the CPU which is the most important thing here.
Anyway, I'd like to finally say if you're planning to buy a VPS, you should think about it carefully. Maybe spend a bit more and get a lower end dedi instead because while on paper its specs may not look as impressive but you will get everything truly allocated for yourself. And your LPM/VPM will be higher.
Good luck and happy spamming :D