Hello -- I'm about to be getting a new PC (notebook), as soon as I decide what I want. I cannot get a new computer very often, so it's important to me to spend a lot of time learning about the different specs before I choose what I want. I've done a good deal of reseach, but I find forums are generally the only the place I can find answers that are really relevant to the information that I'm looking for, so I greatly appreciate any advice/information/suggestions/ect that anyone has to offer. I've got my choices narrowed down to a Dell Studio 15, a Dell Studio XPS 16, an HP HDX16t, an HP dv8t Quad Edition, a Sony Vaio VGN-FW590, and a Sony Vaio VGN-AW390. I have some questions about the options that I'm given for the processor: 1.) First, I'd like to know how much the processor really affects performance. I'm going to be doing a lot of developing/programming and graphics design, as well as a decent amount of gaming, as well as watching a lot of movies (it will be 1080p and have a drive capable of reading/writing Blu-rays). Of course, I'll also be doing a lot of the standard internet surfing, e-mail, and word processing. I'm pretty sure I want a dual processor, and not a quad, and I've been looking over the Core 2 Duo options that come with some of these computers, and I'm curious -- the least expensive option that most of the computers I listed above give me is the Core 2 Duo T6600 with 2.2GHz, 800MHz FSB, and 2MB cache, and the most expensive one offered is the Core 2 Duo T9900 with 3.06GHz, 1066MHz FSB, and 6MB cache. I don't really know what each of these specs mean or how much they affect performance, and I'd be glad to learn about that if anyone has the time, but I'm more concerned with the overall difference in performance between the two processors. In comparing a processor like the T6600 with one like the T9900, how much of a difference would I really notice in the way my computer operates? Also, would I only notice this difference when gaming or working with graphics or other heavy applications, or would the difference in performance be apparent with even simple tasks, like internet browsing or just browsing around the computer in general? I know this is a general question, but I'm only looking for a general answer -- I just want some idea of how much of a difference there is between these two processors, and if it's significant enough that it's worth the extra four to six hundred dollars that it costs. Price is not a particularly huge concern for me, but it is definitely something to be considered for me nonetheless. 2.) I know there is an E model (I forget the exact number) of Core 2 Duo that has 3.16GHz or something like that (even more than the T9900 in other words), but none of the computers that I've narrowed my decision down to have that processor as an option. So, how difficult is it to upgrade to a better processor later on? For example, if I bought the cheapest one (the T6600) with the PC, would it be difficult for me to switch it out for the E model processor (the 3.16GHz one) later on? I'm not sure if I'd want to do this or not, but I'd like to know if it is a reasonable option. 3.) Is there any reason I should consider a quad processor over a dual one. Right now I am inclined to just go with a good dual processor, but are there any reasons that I might want to go with a quad instead? I've done some research on this, and from what I read there seem to be split opinions on which is better, but I'm comfortable with the Core 2 Duo, since I have it on this MacBook and it has been great as far as I know, so I've been leaning towards that, but I just wanted to check. Thank you very much for any help anyone can offer me with this -- it is very much appreciated.