Which is the best quad core processor

I am recently having a dual core processor from amd and i am not so satisfied with the speed of the processor. So i am thinking of upgrading the processor by the purchase of a quad cor processor. So i have many options before me one is the not yet released Q9XXX series which may prove to me the cheapest option. Other one is the the intel core i7 930/920 processor. Probably it will cost me much more. While looking at the compatibility it might not be compatible with my present configuration. Third option is the sandy bridge but don't know what speed it has to offer because it has not launched yet and the last option is the AMD 1090T but i have heard that the speed is not matching up to what the intel has to offer. So suggest me something.

I think so you must first decide it with the budget. Like what budget are you looking at. If your budget is an issue then i would rather ask you to wait for the launch of the sandy bridge. The launch of the sandy bridge will give the necessary quad core processors to go down on their prices and this will help you to select the latest AMD processors or the intel core i7 930. So i would suggest you to wait for the right time and then only decide on getting which processor.

I would rather ask you to stick with the AMD processors. Though right now i may not be having any idea of what processor are you using but there are various amd processors which are priced very low and they stand up and deliver the performance. While its a bit slow from the intel but you cant neglect it. AMD Phenom X4 9650 Processor is available at a price of around 7K(Indian price). While AMD Phenom X4 9850 Quad-Core processor is available at around 8K. So go ahead with the AMD option and it will not disappoint you.

Well let me tell you the details of the every processor that you have mentioned in the question. First talking about the AMD they definitely lack behind intel and also do not have the overclocking headroom. While the i7 processor have more on the efficiency then the raw speed of the processor same is with the i5 processor. The i3 processor lends more flexibility on the GPU sector. If the budget is not the criteria then the gulftown technology introduced in the intel core i7 980X processor is probably the best in terms of the processor speed which gives you a overclocking speed upto 4.3GHz. Probably the best of all. In the sandy bridge processor they are limited to the multi overclocking. They don't have the feature of independent overclocking. So i have given all the features now its upon you to select the best processor for you.