AMD64 Windows vs. Fedora vs. SuSE benchmarks

Illissius writes "AnandTech just posted a review comparing 32- and 64-bit performance on both Linux and Windows. They focused on what is available out of the box without having to compile anything seperately - unfortunately, 64-bit binaries weren't available for most of the Windows benchmarks. To save people the pain of RTFA, there's a very tangible gain moving to 64-bitness, Linux wins some (MySQL, UT2004), and Windows wins some (rendering, RtCW)."

Comments

Note that PostgreSQL has also been optimized...

[tcopeland]

...to work with AMD's 64 bit Opteron. And that was last November, so I daresay it's even better now... check it out here.

PLUG: Good tools, too!

Better article

[ValourX]

I did a 64/32-bit comparison on FreeBSD a while ago, and then did some comparisons in SuSE 9.1.

I haven't gotten around to 3D benchmarking yet, but soon...

-Jem

Re:How can you compare if binaries not avail

[trashme]

While I'm no fan of windows, much like others here, I do see the need to have a *fair* test, and at *many* points through the tests, I saw this: "Again, we had to use 32-bit binaries for the Win-64 beta"

Maybe he was doing his best to test the different 64-bit operating system performance as it stands today. Part of the drawback of Windows is that right now it seems to be pretty hard to get your hands on 64-bit applications.

Oh, and one last part. The writer of the article doesn't quite get that 64bit binarys *should* be faster than 32bit ones, with this little gem:"Here shows another case of 64-bit optimized binaries working faster than 32-bit binaries"

Why?

Why is it so obvious 64-bit is faster than 32-bit? Just because the word size is doubled? For many applications that doesn't help at all. FYI, one of the big advantages of the amd64 instruction set is a larger (than ia32) set of registers for the compiler to work with. That is where the speed boost is most likely coming from. Only certain applications truly benefit from a 64-bit word size.

Re:How can you compare if binaries not avail

[NeoThermic]

>>HHooww iiss iitt ""bblleeeeddiinngg oobbvviioouuss??""

I'ld check the repeate rate on that keyboard. Seems a bit out of sync if you ask me.

In all seriousness, 64-bit computing by itself means that the General Purpose Registers are 64-bits wide. That means increased dynamic range. Using base 2, a 32-bit processor gives you 4,294,967,296 possible values. (which is where the 4 GB RAM limit of 32-bit processors comes from.) That is it's dynamic range.

A 64-bit processor's dynamic range is approximately 4.3 billion times greater than a 32-bit processor, which simply means, it can work with much larger numbers. Thats Important in applications like rendering, mathmatical calculations, and even database servers .

64-bit computing also allows for more RAM than a 32-bit processor because of it's increased dynamic range. As shown, a 32-bit processor can only handle about 4.3 billion values, which roughly works out to about 4 GB of memory. A 64-bit processor has an upper limit of about 18 million terabytes... (32-bit = 0.0043 terabytes... 64-bit = 18,000,000 terabytes), something that I don't see anyone quite needing, but it does mean that your 64bits will go further :)

AMD changed some more things when they designed the Athlon-64.

To start with they used a 40-bit memory address rather than 64-bit since we're not going to need 18 million terabytes of memory anytime soon. Therefore a 40-bit address allows up to 1 terabyte of memory. Thats enough, considering that you won't find a motherboard with support for 1024 sticks of 1GB ram anytime soon.

Then they doubled the amount of General Purpose Registers so there is now 16. So not only have we doubled the number of addresses, we then make them twice as big again. But they can only be used by 64-bit software, so the benefit of extra registers isn't realized with 32-bit software, which is my point. A 32bit app isn't going to excell on a 64bit processor, hence why benching it isn't fair.

After that they lengthened the pipeline by a few stages. In short, you basically make it so higher clock speeds are easier to reach without having to change the format of the processor.

AMD have also built the memory controller into the core, which eliminates almost all latency issues from the CPU to the memory controller. Basically the memory is now just connected to the CPU by wires, whereas the CPU was connected to the northbridge, and so was the RAM. So the northbridge sat between the RAM and the CPU.

Then you have added support for SSE2, so applications designed to take advantage of Intel's SSE2 instructions can now also take advantage of those instructions on an Athlon-64. So now Intel isn't holding the upper hand again.

Finally they are using SOI, which in short, reduces current leakage within the processor, making switching of the transistors more efficent, which means faster speeds and less power consumption.

They've made other changes as well, quite alot more than listed here, but those are the main ones that effect performance.

NeoThermic