Three Generations Of Xeon E3-1275 CPUs
Intel maintained processor interface compatibility between the Sandy and Ivy Bridge-based Xeon E3s, both of which dropped into LGA 1155 sockets. In most cases, upgrading from one to the other was achievable through a firmware update. With the introduction of Haswell, notable changes (such as the fully-integrated voltage regulator) necessitate a new interface called LGA 1150, which naturally requires updated motherboards and platforms.
|Intel Xeon E3-1200||Sandy Bridge||32 nm||LGA 1155||2011|
|Intel Xeon E3-1200 v2||Ivy Bridge||22 nm||LGA 1155||2012|
|Intel Xeon E3-1200 v3||Haswell||22 nm||LGA 1150||2013|
In addition to the interface change that happened between Ivy Bridge and Haswell, Intel also transitioned to 22 nm manufacturing between Sandy and Ivy Bridge, true to its tick-tock cadence. The primary beneficiary of this technology advancement was the mobile segment. But because Intel's Xeon E3-1200 series leverages the same architectures as Intel's Core i3, i5, and i7 CPUs, those mobility-oriented enhancements (primarily affecting power) make their way into the Xeon line-up, too.
Up until recently, the Xeon E5s were all based on the older 32 nm Sandy Bridge-EP/EN architecture. Intel introduced its v2 family at IDF earlier in the month. But the company is still one generation behind in the Xeon E5 series compared to these Haswell-based E3s.
In terms of specifications, the following table compares all three generations:
|Header Cell - Column 0||Xeon E3-1275||Xeon E3-1275 v2||Xeon E3-1275 v3|
|# of Cores||4|
|# of Threads||8|
|Base Clock Rate||3.4 GHz||3.5 GHz|
|Max. Turbo Boost Frequency||3.8 GHz||3.9 GHz|
|Shared L3 Cache||8 MB|
|Instruction Set Extensions||SSE4.1/4.2, AVX||SSE 4.1/4.2, AVX 2.0|
|Thermal Design Power||95 W||77 W||84 W|
|Max. Memory||32 GB, Unbuffered ECC DDR3|
|Max. Memory Data Rate||DDR3-1066/1333||DDR3-1333/1600|
|# of Memory Channels||2|
|Max. Memory Bandwidth||21 GB/s||25.6 GB/s|
|Processor Graphics||HD Graphics P3000||HD Graphics P4000||HD Graphics P4600|
|Graphics Base Frequency||850 MHz||650 MHz||350 MHz|
|Graphics Max. Dynamic Frequency||1.35 GHz||1.25 GHz||1.25 GHz|
|# of Displays Supported||2||3|
|PCI Express Revision||2.0||3.0|
|Quick Sync Video||Yes|
|VT-x with EPT||Yes|
The changes from one launch to the next are apparent, and the most noteworthy evolution, ironically, might be processor-based graphics. Intel is leaning on its HD Graphics 4600 implementation; again, there are no Iris Pro 5200-equipped Xeons. The HD Graphics P4600 engine sports 20 execution units, or four more than the generation prior.