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IBM Mainframe Running World's Fastest Commercial Processor
dcblogs writes "IBM's new mainframe includes a 5.5-GHz processor, which may be the world's fastest commercial processor, say analysts. This new system, the zEnterprise EC12, can also support more than 6-TB of flash memory to help speed data processing. The latest chip has six cores, up from four in the prior generation two years ago. But Jeff Frey, the CTO of the System Z platform, says they aren't trading off single-thread performance in the mainframe with the additional cores. There are still many customers who have applications that execute processes serially, such as batch applications, he said. This latest chip was produced at 32 nanometers, versus 45 nanometers in the earlier system. This smaller size allows more cache on the chip, in this case 33% more Level-2 cache. The system has doubled the L3 and L4 cache over the prior generation."
https://en.wikipedia.org/wiki/IBM_z196_(microprocessor)
Palm trees and 8
That's a Ming Mecca chip. Those aren't even declassified yet!
CPUs have not accessed main memory synchronously in decades. There are many hundreds of cycles lost if the processor stalls on a RAM access, not just from the length of the wiring but the addressing logic too. In fact, modern CPUs don't do word-level access to RAM, but rather pull in whole cache lines in a more packetized memory access protocol. Even in a multi-CPU SMP system, they don't actually communicate through system RAM anymore, but rather communicate CPU-to-CPU with a cache coherency protocol that provides the illusion of a shared system RAM. Each CPU really has its own set of local RAM behind its own cache and on-chip memory controller.
Even the L2 or L3 caches are unable to keep up with the CPU, but they are still significantly faster than system RAM, so they still help when the working set can fit there.
No, they aren't claiming that. Clock speed is still extremely important, though, and nobody else except IBM has figured out how to hit these high gigahertz numbers, much less within power and cooling constraints. What's all the more impressive is that IBM does it at mainframe service qualities, i.e. this machine runs continuously at 5.5 GHz without shutting off cores, without "burst" mode, and without weird/exotic stuff like cryogenics that might keep a chip running long enough for a screenshot. It's just balls out performance on every thread -- and there's a definitely a market for that. Nobody else is left doing this computer engineering, bless them. Also check their cache sizes (obscenely huge), out-of-order execution, pipelining, crypto and decimal floating point in every core, extremely complex instructions like transactional execution.... This z CPU is a gorgeous piece of engineering in every way. And no, you can't run an entire large bank (for example) on your laptop.
L3 is 48MB, (see p. 43), not GB as The Register had it, thanks for noticing that.
As always, all IMO. Insert "I think" everywhere grammatically possible.