AMD Athlon 64 only with 256 kB L2 cache?
There have been discussions for a few weeks about the cache sizes of the Athlon 64, which will be the successor to the Athlon XP at the beginning of next year. So far, many have assumed a 1 MB L2 cache, but now a 256 kB L2 cache seems to be manifesting.
The Opteron, the, and that, is certainly not entirely innocent of the current confusion confirm official and unofficial documents (Fig. 4 and 5), will be equipped with a 1 MB cache. Thanks to this large cache, it will also have around 100 million transistors and would therefore be twice as complex as the 0.13 µm Pentium 4 (54 million transistors). The Opteron's processor core is said to be 180 mm² (Pentium 4: 131 mm²).
But what about the Athlon 64, formerly codenamed Clawhammer-DT? An old but unofficial roadmap (Fig. 3 and 4) clearly and unequivocally speaks of a 256 kB L2 cache. However, an official AMD document from October stated that there will be products based on the Clawhammer-DT with 256 kB and 1 MB L2 cache . The small version with a small cache was quickly traded as a Duron descendant. As a large American magazine now reports, only 256 kB are actually provided for the Athlon 64. The processor core of the Athlon 64 should only have a size of approx. 105 mm², which indicates significantly fewer transistors than the Opteron.
This raises the question of which of the documents available to us can be believed. Actually, only age speaks against pictures 3 and 4. Because these two roadmaps are from the end of July, but the cache sizes agree with the last reports. The fact that AMD could not keep to the schedule it had set itself and, contrary to expectations, on a 333 MHz FSB (XP2700 +,2800+) was certainly not foreseeable at the time. The age does not speak against the information from the official AMD document, because it is only a month old, but it is surprising that the Clawhammer-DP, a version of the Athlon 64 that is suitable for dual-processor systems, is still here AMD had previously discarded. This is also confirmed by the last official AMD roadmap from November 27, 2002 (Fig. 2). The Clawhammer-DP, which was still listed on a roadmap from July 27, 2002 (picture 1), has now disappeared.
If it should be true that the Athlon 64 actually only has 256 kb L2 cache will come, then he could have as difficult a problem with the last Athlon XP core, the Barton, as the first Pentium 4 (Willamette) of its time with the last Pentium III (Tualatin-S). Just like the Barton, the Tualatin also had a 512 kb L2 cache, the Willamette had to be content with 256 kB and thus had a really difficult position in the past. It had to admit defeat to the last Pentium III model not only once. One can only hope that the Athlon 64 does not suffer the same fate in the fight against the Barton.