Clovertown scores revealed

Clovertown (2GHZ, 65nm, 2x4MB L2, FB-DIMM) slower than Athlon 64 (2GHZ, socket 939, 512KB L2, DDR)

Intel showed off Clovertown quad-core server CPUs running on the Bensley platform with FB-DIMM memory at Spring IDF Taipei. Clovertown is basically two 65nm Conroe CPUs stacked together, with total of 8MB L2 cache. This page contained the benchmark scores for a 2P Clovertown. The reported clockspeed was 2GHZ (could be 2.13GHZ, same as Conroe E6400).

For single threaded test, the 2GHZ Clovertown got a Cinebench 9.5* score of 362. Daniel J. Casaletto, Intel Vice President, Digital Enterprise Group Director, Microprocessor Architecture and Planning, was running the demo. For 2P 8 cores, the score scaled to 1723, or 4.7x. Adding 7 cores led to 3.7x more performance. I think this is quite poor, you get only about half a core's worth when you add a core.

FSB (Front Side Bus) is an Intel bottleneck. Eight Conroe cores fighting for a 1066MHZ FSB is not a pretty sight: in 2P Clovertown each Conroe core gets only 133MHZ bandwidth or 1GB/s, not much better than a 80486 (Well, you may say there is the dual bus, so it should be 266MHZ, but 8 cores of cache coherence traffic must be considered). Fortunately, Cinebench doesn't put a lot of load on the bus, it spends most of the time digesting the data.

Let's pay more attention to this photo here, which shows the 2P Clovertown in action and is quite exciting. Look at the upper left corner, it reads Cinebench 64 Bit Edition. Finally, we can see Intel got 64 bit working, it's running the 64 bit version of Cinebench! My congratulations to the Israeli engineers for getting AMD64 figured out. Welcome to the exciting world of pervasive 64bit computing! Now, Microsoft will allow the world+dog to go 64 bit.

A reader kindly provided us the CINBENCH 64bit Edition result for a 2GHZ socket 939 setup. The spec: Athlon 64, Socket 939, 90nm, 2GHZ, 512KB L2. The score: 370. <--click to view screen capture.

On my old Athlon 64 2800+ (1.8GHZ, Socket 754, 130nm, 0.5 MB L2 cache), I got a 64 bit Cinebench 9.5 score of 294. My ClawHammer is a bit slower than Conroe CORE, but only a little. If you consider my CPU is only 1.8GHZ and only uses single channel DDR, and my old PC only has integrated S3 UniChrome graphics which eats some memory, it's quite good. I managed to overclock it to 1.9GHZ and got a score of 312. I expect the three year old ClawHammer to get a score 0f 294*2/1.8= 327 at 2GHZ, within 10% of the future Conroe. So I feel I made a good investment buying AMD* - I paid less than $100 for the CPU+MB.

Clock for clock, the performance of Intel CORE (Merom/Conroe) is very close to socket 939 Athlon 64 . Mooly Eden definitely over-exaggerated Conroe performance.

So far, Intel is trying to follow AMD's footsteps. Conroe is still a few months away, and AMD is a moving target. Dirk Meyer said AMD will soon release a higher capability product besides changing from DDR to DDR2. With the new process technologies jointly developed with IBM, AMD can boost clockspeed by an upward of 40%.

The Conroe performance analysis is here. I pointed out that when working set is larger than Conroe's unified cache (4MB), Conroe performs slower than Athlon64. Conroe only shines in simple and single threaded tests where the whole working set sits inside the 4MB unified cache. The Cinebench 9.5 needs over 150MB to run. Clovertown's 8MB cache has some positive benefit, as Cinebench works on the scene top down, only a slice of the scene is being worked on at any moment of time . But still, the effect of the 2x4MB cache is much smaller than the cases where the working set sits inside the cache all the time.

In other news, AMD subpoenas Microsoft in its anti-trust lawsuit against Intel. From the documents it's seeking, AMD is clearly suspecting that Intel hindered the development of Windows for AMD64.

* Cinebench is essentially a CPU/Memroy performance test, it can be downloaded from cinebench.com .

* I bought the CPU+MB (with S3 IGP) combo for $79 at Frys, nowadays, such deals are impossible to find.

*I am interested in seeing some Clovertown and Sempron socket 939 comparisons. If you have such a machine running Windows x64, please submit your results in the comments. Don't under estimate AMD desktop CPUs, check out this Athlon 64 and Xeon comparison.

There are several people keep posting 32 bit benchmarks for Athlon 64. Please note Intel was doing a 64 bit Cinebench 9.5 . That's why Intel got a high score of 362 at 2GHZ. As I can see from posts by users on the internet, a Conroe at 2.4GHZ gets about the same score. So, please read the benmark condition: 64 bit edition of Cinebench 9.5.