Who knows what 58xx and 3xx series will do to that bandwith. *shrug*
I think, generally speaking, any of the comparisons between P55/X58 are moot. Sure, its BS that intel is screwing people with the socket changes and differences, but regardless of that i7 architecture is i7 architecture. We'll know in a matter of days if intel changed anything with the P55 version of i7 that actually gives a performance difference.
Why dont we all just take a big, deep breath and wait a few more days instead of spreading rampant speculation?
I'm speaking simply of fact, I already know full well what Intel did with the P55 "chipset" compared to the X58 chipset. I can make comparisions all I want as the facts are already out there. Interesting fact, if you have a X58 based system, you already pretty much have a P55 chip in your system.
*NOTE - NONE OF THE DIFFERENCES BETWEEN THE TWO LINES DO NOT, I REPEAT, DO NOT EFFECT PURE CPU-ONLY PERFORMANCE* - Its quite possible for *JUST* the CPU, in CPU ONLY intensive programs on LGA1156 to outperform an LGA1366 CPU at stock settings. I just want to make that fact clear before I go ahead and make comparisons.
P55/LGA1156 - Hardwired PCIe 2.0 x16 lanes(can be spilt into 8x/8x or 8x/4x/4x) + 1 DMI link in the CPU, hardwired x16+DMI link provides total bandwidth of
8-9GB/s between CPU and the rest of the system(GPU's, etc), P55 "chipset"(more like southbridge) connected via DMI link which is the equivelent of a PCIe 1.0 4x link, P55 provides an additional PCIe 1.1 x6 lanes, Memory and other Northbridge functions integrated into CPU - P55 is the SAME, yes you read this correctly, the SAME chip used as the southbridge in the X58 platform, contains the ICH10R.
X58/LGA1366 - 1 QPI link in SP systems(i7), 2 QPI links in DP systems(Xeon), each 1 QPI link provides total bandwidth of
19-25GB/s between CPU and the rest of the system(GPU's, etc), X58 chipset connected via 1 link QPI link per CPU, X58 chipset provides PCIe 2.0 x40 lanes(can be split in any way wanted/needed) + 1 DMI link, Memory and *most*(but not all) Northbridge functions integrated into CPU, connected to P55 via DMI(yes, you read that correctly) to provide southbridge functions, read above for more info on P55.
Thats the pure facts, fair and simple, in single GPU, and dual mid-level GPU set ups? A P55 system will rarely limit you, anything fancier(PCIe RAID cards, Dual/CFX/SLi High-End GPU set ups, etc) and you'll be wishing for the extra breathing room in the X58 chipset. Hell, for some extreme set ups, EVEN the bandwidth provided by X58 is limiting!