According to VR-Zone's report, 512KB of L2 cache will return to the Athlon 64 in a new "Winchester" core that's due out in the Q4 of this year. Winchester will apparently feature a dual-channel DDR2 memory controller and be built using 0.09-micron fabrication technology.
Update (Scott): I believe DigiTimes was the original source of this story, though VR-Zone didn't credit them. Here is the relevant part of the DigiTimes report:
Advanced Micro Devices (AMD) should launch its new 939-pin Athlon 64 processors in the second quarter of this year as expected, said sources at Taiwan’s motherboard makers.Of course, DigiTimes is probably wrong to say the Athlon 64 FX will have 256K L2 cache. If anything, the non-FX variants would get the piddly cache.
The new Athlon 64 FX processor, codenamed Newcastle, supports dual channel DDR memory and will boast 256KB of L2 cache, instead of 512KB as reported previously. The new processor will be available at speeds ranging from 1.8GHz to 2.4Ghz.
AMD is also expected to add another 939-pin processor, codenamed Winchester, in its 64-bit lineup in the second half. The Winchester will be made using a 90nm process, not the 0.13-micron process employed in the Newcastle.
Update II (Scott): Scratch all of the above. The grapevine has spoken, and we now believe the 256K L2 cache rumors are just plain wrong.