64-bit compatibility
more memory addressability
Intel Xeon
Spätestens ab jetzt wird man doch wohl dicke 64-Bit Tests Xeon vs. Opteron fahren dürfen. Einen habe ich schon gesehen:
64bit Opteron vs. Xeon
In dem Test wird ein Dual-Opteron-248-System gegen ein 3,6GHz Dual-Xeon getestet, sie machen fairerweise darauf aufmerksam:
Intel Xeon 3.6GHz “Nocona”: $930
Intel Xeon 3.4GHz “Nocona”: $725
AMD Opteron 250 (2.4GHz): $825
AMD Opteron 248 (2.2GHz): $700
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“Software IOTLB — Intel EM64T does not support an IOMMU in hardware while AMD64 processors do. This means that physical addresses above 4GB (32 bits) cannot reliably be the source or destination of DMA operations. Therefore, the Red Hat Enterprise Linux 3 Update 2 kernel "bounces" all DMA operations to or from physical addresses above 4GB to buffers that the kernel pre-allocated below 4GB at boot time. This is likely to result in lower performance for IO-intensive workloads for Intel EM64T as compared to AMD64 processors.”
Although this shouldn't affect people that run with under 4GB of memory, this is an important point to note. If you do ever need the extra memory, you may take a performance hit. Unfortunately, we do not have over 4GB of DDR2 memory here today so we will not be able to test how much of a hit you would take if any.
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Die passende Fußnote zur ersten Zeile des Werbebanners.
Grüße,
Tom