CPUs, what are they? (GUIDE)

The CPU is the "brain" of the computer essentially. It controls everything the computer does. CPUs are composed of millions of microscopic transistors packed on to a silicon die. The complexity of how they're built is astounding. Current transistors are typically 65nm – 45nm, with 32nm coming at the end of 2009. The CPU also has memory onboard, known as cache. A typical processor will have 32-64KB of L1 cache, 2-12MB L2 cache, and the newest processors have 8+MB L3 cache. The cache is allocated per core, so a processor with 64KB L1 cache usually has 32KB per core. The same goes for L2 cache. L3 cache is shared for all cores, so if a processor has 8MB of L3 cache, it shares 8MB for the whole processor. The cache is used to store instructions for the processor to preform. It gets very complicated, so I won't delve too much in to it. Anandtech has some good articles regarding CPU structure.

Dual core and Quad core processors are the most common. Dual core means the processor has two individual cores operating on the same die, and quad core has four processors on the same die. The advantage of having more cores is mainly for multitasking. Not all programs support more than one core, and even fewer support more than two. Future games and programs will have support for four cores and above however.

Two major companies manufacture CPUs. They are Intel and AMD. Intel is currently leading in performance with its groundbreaking Core 2 line of processors and the new i7 line. AMD has fallen behind recently with the Phenom processor, but recently released the Phenom II which closed the performance gap a bit. Here is a list of current processors and their price as found in newegg in USD (as of 3/1/09)

INTEL

Core i7 (socket 1366)

Quad core

i7 965 EE* 3.2GHz - $999
i7 940 2.93GHz - $560
i7 920 2.66GHz - $289

Core 2 (socket 775 unless otherwise noted)

Quad core

45nm

QX9775 EE (socket 771) 3.2GHz - $1550
QX9650 EE 3.0GHz - $1030
Q9650 (12MB)*** 3.0GHz - $325
Q9550 (12MB) 2.83GHz - $280
Q9400 (12MB) 2.66GHz - $230
Q9300 (6MB) 2.5GHz - $240
Q8300 (4MB) 2.5GHz - $190
Q8200 (4MB) 2.33GHz - $170

65nm

Q6600 (8MB) 2.4GHz - $198

Dual core

E8600 (6MB) 3.33GHz - $270
E8500 (6MB) 3.16GHz - $188
E8400 (6MB) 3.0GHz - $165
E7500 (3MB) 2.93GHz - $140
E7400 (3MB) 2.8GHz - $120
E7300 (3MB) 2.66GHz - $130

Pentium Dual Core**

E5400 (2MB) 2.7GHz - $96
E5300 (2MB) 2.6GHz - $85
E5200 (2MB) 2.5GHz - $73
E2220 (1MB) 2.4GHz - $73
E2200 (1MB) 2.2GHz - $70

Celeron**

E1500 (512KB) 2.2GHz - $62
E1400 (512KB) 2.0GHz - $50
E1200 (512KB) 1.6GHz - $47

*EE – Extreme Edition (unlocked multiplier for overclocking)
**Pentium dual core and celeron are 65nm CPUs. They are basically Core 2 chips that were defective, and intel "turned off" the non-functioning parts and made a low end chip.
***L2 cache size. Higher L2 cache usually performs better.

I won't get in to single core, because they're really not even worth looking at in this day and age.

AMD (Socket AM2+ unless otherwise noted)

45nm

Phenom II X4

X4 940 [6MB]** 3.0GHz - $229
X4 930 [6MB] 2.8GHz - $190
X4 810 [4MB] 2.6GHz - $185 (Socket AM3)

Phenom II X3*

X3 720 [6MB] 2.8GHz - $145 (Socket AM3)
X3 710 [6MB] 2.6GHz - $119 (Socket AM3)

65nm

Phenom X4

X4 9950 [2MB] 2.6GHz - $170
X4 9850 [2MB] 2.5GHz - $155
X4 9750 [2MB] 2.4GHz - $164
X4 9650 [2MB] 2.3GHz - $154
X4 9600 [2MB] 2.3GHz - $100

Phenom X3*

X3 8750 [2MB] 2.4GHz - $120
X3 8650 [2MB] 2.3GHz - $88
X3 8450 [2MB] 2.1GHz - $93

*X3 CPUs have 3 cores. They're X4 CPUs with one disabled core

**L3 cache size

I won't get in to the older X2 Athlons because they're outdated.

Those are pretty much all of the CPUs you want to consider when building your computer.

Architecture: It's not all about the gigahertz

The architecture of the CPU varies between different different cores, which is why you can't only base your purchase on the speed of the processor. A 1.8GHz Core 2 Duo will be faster than a 3.73GHz P4 EE in every task because the architecture of the Core 2 Duo is much more efficient; it gets more done per clock than the old netburst architecture of the Pentium 4. As CPUs get smaller and shift between manufacturing size (65nm to 45nm, etc.), they become more efficient, using less power and running cooler. They also tend to run faster than previous generation processors. When changing architecture like from Core 2 Duo to i7, there is a very large gap in performance in multimedia tasks and a smaller gain in gaming.

I may add more to this later.

whats ur purpose of doing this i think most of us here knows what a cpu isDemetriP790

For the FAQ. Also, I'm sure there are a few people here that don't know what a CPU actually does. Also, I included a price list of all the current CPUs.

Is it really the brain? Or is the chipset the brain? What about the BIOS? :PX360PS3AMD05

Even if you wrote a pretty good guide, you forgot to tell what exactly is the full form of "CPU".gigatrainer

Anyway All I care About a Processor is how they Act in Gaming For Several Benchmark such as Legionhardware cpu Scaling test
http://www.legionhardware.com/document.php?id=807&p=15
http://www.legionhardware.com/document.php?id=775&p=14

For me a Good Differance Beetween cpu is 5-10 Fps : and an One that worth changing you'r CPU & motherboard perhap is 30% / 50% boost minimum Like if it was Giving 30fps and by simple fact to change cpu you'd get 47-49fps just from the cpu : + Same video card setup

Example 4600x2 2.4Ghz Athelon Socket am2 Vs Core2 Duo E8600 3.3Ghz Stock
So if you'r guide is to explain how user to understand differance within cpu such test could Worth Gold or Diamond :P

you forgot the phenom 9500/9550 on your list