Originally posted by boxie
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Fact is, Linux on Mainframes and Linux on x86 runs the same source code. On Mainframes, the Linux software is many times slower. Who says that? A guy who ported Linux to Mainframes. He could compare the same software running on Mainframes and on x86. In the links, a consulting firm said that the z9 cpu is slower than a single core 900 MHz Xeon. Every IBM z cpu after that, has been just something like 50% faster than the z9. The z10 cpu is 50%, which corresponds to a single core 1.35 GHz Xeon. And the next cpu, the z196 is again 50% faster which means z196 is as fast as a Xeon single core cpu at 2 GHz. Or a dual core Xeon cpu at 1 GHz. And if you continue increasing performance 50% until you arrive the z14, you will see that z14 is something like 2-3 GHz dual core Xeon. But today Intel have 22 core 2.4GHz Xeons. Guess which is faster?
IBM is famous for posting FUD and false claims. And whenever IBM has a good result, they post it all over the internet. For instance IBM POWER7 was a good cpu and really fast, faster than anything else. IBM posted lot of benchmarks on their website and all over the internet was SPECcpu2006, TPC, SAP, etc benchmarks that really proved that POWER7 had the highest scores. And it did. But for Mainframes? No benchmarks. Nope. Nada. Zilch. No benchmarks nowhere. Why? If Mainframe cpus smokes everything on, say, SPECint2006 scores, IBM should have submitted results to SPEC organization. But there are no results. Nowhere.
I remember IBM claimed that the largest z10 Mainframe with 2TB RAM, could replace 10.000 x86 servers. That is really surprising, if you know that Mainframe cpus are dog slow. So I dug a bit. It turned out that all x86 servers were old and antique (256MB RAM P3) and they all idle at 1-2% cpu load. And the Z10 Mainframe was loaded at 100%. So it is probably true that one Z10 Mainframe can virtualize 10.000 x86 servers that all idle. However, what would happen if 10 of the x86 servers started to do real work? The Mainframe would choke to death trying to keep up.
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