Man, i hate this!!!
choosing a CPU!! the things u have to go thru, just when you have made up your mind, they put something new out!
This happens to everybody, you're not alone. Generally the cure for this is to wait until you really need a new computer before you buy one. Your current machine not cutting it will spur you to replace it as soon as possible so you won't be tempted to wait any more.
I read thru alot of the forums and the official sites of both Amd and Intel.. and looking at Toms cpu chart and benchmarks, C2D is better than both AMD athlon64x2 and intel P.D 9xx
Manufacturers' websites are generally good sources of technical information about the products but are notoriously poor at giving *competitive* information. It would be like Ford putting on their website that Chevy trucks are more reliable- you're just not going to see it.
Sites like Tom's are decent at evaluating the processors and determining which one is better at certain things. However, your mileage may vary with how you use your machine and what you run on it. I run very few applications that Tom's uses to benchmark their CPUs with and as such, I generally look at broad trends. Here is a brief summary of their reviews:
1. Pentium D 800s are basically two P4 Prescotts put together on one CPU package. This makes extremely hot-running CPUs that are beaten by each and every AMD Athlon X2 and Core 2 Duo unless they are overclocked wildly, such as the Pentium D 805 that Tom's got up to 4.1 GHz (burning several hundred watts just on the CPU in the process!)
2. The Pentium D 900 series are improved versions of the Pentium D 800 that have more L2 cache but basically their main advantage over the 800s is that they run significantly cooler at the same speeds. But they're still quite hot. The upper range of the Pentium D 900 series (945, 950, 955EE, 960, 965EE) are competitive in performance to the lower-end Athlon 64 X2s and Core 2 Duos.
3. The Athlon 64 X2 series are very good processors based on the Athlon 64 architecture. They consist of only one processor die with both cores on it and have an integrated memory controller and a HyperTransport serial bus to talk to the chipset instead of a frontside bus that does both functions. The X2s are somewhat slower clock-for-clock than the Core 2 Duo CPUs, especially in programs that heavily use SSE optimizations (some encoders, many games) but the X2 line has higher clock speeds than the Core 2 Duos do, so performance is similar up until the high end, where the Core 2 Duos have clock speed parity and outpace the X2s.
4. The Core 2 Duo is basically a heavily massaged Core Duo, which is in itself a heavily massaged dual-core version of the Pentium 3 as opposed to the Pentium 4-based Pentium Ds. This means that the Core 2 Duo runs far cooler than the Pentium Ds and performs much better. The Core 2 Duo line has the overall performance crown with the Core 2 Duo X6800 beating the AMD X2 line. The Core 2 Duo series is very well-regarded for overclocking prowess, while the current 90 nm X2 line doesn't go much above 3.2 GHz no matter what you do to it.
5. The Core 2 Quadros are made up of two Core 2 Duo dies stuck together in one CPU package, similar to how the Pentium Ds were two Pentium 4s stuck in one package. These chips are currently very expensive and run very hot- similar to the Pentium D 800 series. Clock speeds are 2.67 GHz and 2.40 GHz and performance is similar to the similarly-clocked Core 2 Duos in single or two-threaded applications. Programs that can use 4 cores will run much faster on the C2Q than the C2D, but on Windows, basically that's limited to some video encoders and rendering software.
6. AMD's QuadFX is basically a dual-Opteron workstation that's priced very aggressively and uses normal unbuffered RAM instead of ECC RAM used in the dual or quad Opteron setups. The QuadFX has three dual-core processor pair sets- the FX-70 (2.6 GHz) FX-72 (2.8 GHz) and FX-74 (3.0 GHz.) The FX-74 is competitive with the QX6700, with the QX6700 generally winning the single-threaded game benchmarks and the FX-74 winning most other benchmarks. The FX-70 is probably the most intersting as it's the least expensive way to get four cores (roughly $1000 for CPUs + motherboard while a single Q6600 is something near $900) and the QuadFX motherboard is upgradeable to two quad-core CPUs when they come out later this year.
but what bothers me is..
AMD's new AM2 athlon64x2 processors got twice as much fsb than C2D, 2000mhz where as C2D 1066mhz. not to mention AMD has a total memory bandwidth of 20Gb/s where as intel mama-boards' total is only 10.8Gb/s! The cpu speed difference isnt that much of a deal, comparing C2D
e6600 with am2 athlon64x 4800+ ,both of them at 2.4Ghz and 4mb cache (intel's 2 cores share the cache, where as amd has 2mb separate cache dedicated to each core!)
doesnt more Fsb mean better flow? with better flow and more memory bandwidth mean better overall better performance?
Like Jack said, the AMD CPUs don't have an FSB. K8 CPUs have an integrated memory controller that links directly from the processor to the RAM. Socket AM2 Athlon 64 X2s can handle dual-channel DDR2-800, so they have a memory bandwidth equivalent to what a 1600 MHz FSB can provide. They also have a HyperTransport serial link between the CPU and chipset that's capable of pushing 2 bytes per clock at a rate of 1 GHz in both directions at one time. This gives 4 GB/sec in bandwidth in each direction simultaneously between the CPU and chipset. Intel's FSB carries both memory data and CPU <-> chipset traffic, although there is not that much of the latter and in Intel's case, much of what has to go through AMD's HTT link does not even hit the CPU as Jack also noted.
AMD's CPUs have more bandwidth than they can handle at the present, which is why the transition from socket 939 to Socket AM2 doubled the memory bandwidth that the CPU got but didn't increase performance. This will greatly benefit them when quad-core CPUs come out, but it doesn't do much now. Intel's FSB can't scale that much further than it already has, but Intel coupled a reasonably memory-miserly processor in the Core 2 Duo with a ton of cache and excellent prefetching algorithms to extract the most out of the old FSB. Intel also made some key architectural improvements, particularly the ability to execute SSE instructions in one clock tick instead of two (like all previous CPUs do.) As such, the C2D performs excellently on applications that use SSE instructions heavily, like games and certain encoders. That is why the Core 2 Duos are faster than the Athlon X2s even though AMD's CPUs are awash in bandwidth and Intel's are not.
The Core 2 Quadro is about as much as Intel's FSB can handle at the present, so watch to see what Intel does when it wants to make an 8-core CPU. I'll give you a hint: Intel is making a 1300-some-odd pin socket for these CPUs and it's not because they need 600 extra pins for extra power. The LGA 775/771 sockets provide enough of that.
even after all the spec shown above clearly amd "seams" to be better than C2D e6600, but everywhere i check e6600 is way better than amd - how is this possible, what does C2D have that amd doesnt?
The E6600 doesn't beat every AMD chip in everything. Put the E6600 against a 5400+ or 5600+ and watch the E6600 get shown the door in almost all applications. The Core 2 Duos are extremely good at integer and SSE math and applications that use that heavily will favor the C2D. Number-crunching applications that don't use SSE much and hit the RAM very heavily will favor the AMD CPUs and their superior non-SSE floating-point performance and increased memory bandwidth.
check this out: e6400 ties amd 4800+ inthe benchmark of unreal tournament(and almost everything)..so which one of these is better now?!
Whatever one you can build a system around that suits your needs best and for less money. Generally, Core 2 Duo chips will give a better bang for the buck in gaming due to the heavy use of SSE in the games.
Doesnt speed of the processor make a difference? PD960 with 3.6ghz everything same as C2D but only difference is the fsb, with PD960 with 800mhz and C2D with 1066mhz? so how come C2D even e6300 is faster than top range in PD (960)?
The Pentium D and Core 2 Duo (also Athlon X2) are wildly different architectures. The Pentium D doesn't do much with each clock tick, so it needs a lot of them to get things done. The Pentium Ds were beaten by the Athlon X2s, and since the Athlon X2s get beaten in games by the Core 2 Duos, it stands to reason that the Core 2 Duos are a ton better at games than the Pentium Ds. The speed of the CPU determining performance can only be compared when the architecture is similar.
The FSB is simply a pathway to get data to and from the core. The Pentium D 955EE and 965EE's FSBs might run at the same speed as the Core 2 Duos' do, but what's behind the FSB couldn't be more different.
and what difference does it make if a cpu has a total 4 or 2mb cache?
L2 is basically extremely high-speed RAM that's on the CPU die. More L2 means that the CPU doesn't need to wait for data to come all the way from RAM before it works on it. If the path to the RAM is very slow (such as it can be while going through the FSB) or your CPU core is extremely hungry for data, increasing the L2 size has massive performance gains up to a certain point. That point seems to be 2MB or under, so going from 2MB L2 -> 4MB L2 brings a small (roughly 7%) gain in speed for the Core 2 Duo, not a very massive gain.
im not planing to overclock this time, as i already have fried a cpu and the mama board, including a hole in my wallet from the way i spent so much on it
so please answer disregarding over clocking, and processors such as en6700, C2Dextreme, athlon64-fx, extreme cpus which i cant afford.
so out of e6400,PD950(3.4ghz,4mb),PD945(3.4ghz,4mb), amd 4600+(2.4ghz,2mb),4400+(2.2ghz,4mb) which should i buy?
First of all, disregard the Pentium Ds. The Athlon 64 X2s and Core 2 Duos are far better CPUs. I assume that you're gaming, so the E6400 and X2 4600+ will perform rather similarly with games. 2x1MB L2 cache AMD CPUs don't perform that much better than AMD CPUs with 2x512K L2 (gain is about 7-8% tops, just like 2M vs. 4M C2Ds) so the 2x512K models would be the ones you want as they're less expensive than the 2x1M units.
If I had to recommend a CPU...it would probably be the AM2 4600+ as it's $208 versus the $230 of the E6400. Performance will be similar in games and a decent AM2 motherboard is generally a little less expensive than a decent Core 2 Duo board, too. However, this assumes you swore off OCing as you said. The E6400 will OC MUCH better than the 4600+ will.
Excellent post MU_Engineer.
These are the posts that makes the forums look unbiased.
Also, you forgot K8's 64-bit advantage over C2D and QuadFX advantage over intel's dual-die kentsfield on Windows Vista thanks to a better NUMA handling. Don't forget that C2D is prone to cache trashing due to the nature of the shared L2 cache.
Every processor (call it AMD or intel) has their ups and cons.
In conclusion, it all depends on the apps you use for a living.