Hey guys,
the launch is still almost half a year away, but i thought id post a second thread with some details so your already prepared for "Core i5" and the new 1156 platform and how to clock it. Ill try to post more details here bit by bit as i have the time and new rumors appear on the net
First lets look at the parts, intel is apparently following the same strategy as with Core i7
They will only use very few SKUs, 3 cpus for socket 1156 at launch with more to follow, but like with i7, with each introduction 1 will be EOL'ed most likely.
So there will be an overlap of more SKUs but its rumored that there will only be 3 non igp and 3 igp cpus (plus some LV versions of those) maintained at the same time.
"Core i5 935" 2933MHz
4cores 8threads VTT TXT
Bclock 133
QPI Multiplier 16x *3(2133MHz/4.3GT/s)
CPU Multiplier 22x (2933MHz) 23x (3066MHz)*1 27x (3600MHz)*2
Uncore Multiplier 15x (2000MHz)
Memory Multiplier 10x (1333MHz)
"Core i5 925" 2800MHz
4cores 8threads VTT TXT
Bclock 133
QPI Multiplier 16x *3(2133MHz/4.3GT/s)
CPU Multiplier 21x (2800MHz) 22x (2933MHz)*1 26x (3466MHz)*2
Uncore Multiplier 15x (2000MHz)
Memory Multiplier 10x (1333MHz)
"Core i5 915" 2666MHz
4cores 4threads
Bclock 133
QPI Multiplier 16x *3(2133MHz/4.3GT/s)
CPU Multiplier 20x (2666MHz) 21x (2800MHz)*1 24x (3200MHz)*2
Uncore Multiplier 15x (2000MHz)
Memory Multiplier 10x (1333MHz)
*1 Turbo Mode with 4 cores active
*2 Turbo Mode with 1 core active
*3 according to some sources all i5 cpus still use QPI, either to connect the igp chipset to the cpu on the cpu package, or to connect the pciE interface to the rest of the cpu inside lynnfield. The multiplier seems to be 16x however, which would allow bclocks of up to 250mhz compared to 222mhz with an 18x multiplier, which is the lowest qpi multiplier the 1366 platform supports
1156/P55 compared to 1366/x58:
lower cpu clocks
lower uncore clocks
Less memory channels (2 vs 3)
higher memory clocks possible (uncore has to be 1.5x mem clock, not 2x like on i7)
higher bclocks possible (min qpi multiplier is 16x, which allows up to 250bclock without breaking the 4ghz/8GTs limitation)
igp cpus dont have an imc (imc is inside the igp chip on the cpu package, and its P45 based, not i7 based)
non igp cpus have an i7 based imc
Less pciE lanes (16 vs 32)
new hdd cache (only on p57?)
lower to identical cpu price
lower to identicl mainboard price
1156/P55 compared to 775/p45:
higher cpu clocks
better igp performance (~2x g45)
Better uncore to memory ratios (memory multipliers)
new hdd cache
identical to higher cpu price
identical to higher mainboard price
so you get the picture, its about taking 1366/x58 and making it cheaper so it can go mainstream.
time will tell whether the edges have been cut too much or just right
In the end 1156 will be in between 775 and 1366, so there will be 3 sockets in the desktop segment actively supported at the same time, so far we always had one actively supported together with the last gen socket fading out, and in recent years intel did an amazing job keeping 775 alive, which means we have lived with one socket for the recent years, so adding 2 more sockets is quite a brave and questionable move.
Btw, the name i5 is not decided yet it seems, it will most likely be called something entirely diferent, not even core, but ill go along and call it i5 like everybody else in this thread. The new platform will be the mainstream to entry level version of 1366 and i7. actually the positioning isnt exactly clear and intel might not even have decided it yet. it could go all the way from entry level up to performance or even highend and only leave the ulra highend to 1366, or it could only be the entry level up to mainstream and leave the performance up to ultra highend to 1366. I suspect something in between...
intel definately plans to keep 1366 alive in the highend desktop/workstation segment and as such will release the fastest cpus for 1366 only. so 1156 cpus will always be one bin below that of the fastest 1366 cpu.
cpu prices for i5 should be between 200$ and 300$ at launch, possibly above that depending on how intel plans to position it. there will be 100$ and even cheaper i5 cpus eventually, but dont expect them soon after the launch. mainboard prices for i5 should be between 100$ and 200$, so 50-200$ cheaper than 1366 mainboards.
Core i5 has an integrated pciE controller, so 16 lanes will directly go to the cpu, while extra pciE lanes are available through the south bridge that is directly connected to the cpu. this connection is the dmi bus, which intel has used to connect the sb to the nb since the 915 chipset many years ago. this dmi bus is actually a slightly modified pciE bus and is pretty much 4pciE 1.1 lanes bundled together to one link. thats not a lot of bandwidth considering this bus is used for all onboard devices, hard drives, sound, lan, and tv cards or other add in cards. so if you really push things with raid or tv cards etc, expect this bus to hold you back.
dont expect a performance boost from the integrated pciE controller on the cpu, it actually does help performance, but the improvement is tiny.
another thing is that some boards youve probably seen have 3 pciE 16x slots. unless they use a pciE switch like PLX/NF200 or hydra the third slot will be very limited since it actually comes from the soutbridge. the southbridge ironically has 4 pciE 2.0 lanes, but those are actually 1.1 lanes which are 2.0 device compatible...
so its more of a marketing 2.0 thing... dont plan to use those third pciE 16x slots for tri vga setups, i doubt nvidia would allow it anyhow.
which brings up the next thing, sli on P55... will it work without NF200 chip? its still not set in stone but it seems nvidia will continue the same strategy they had with x58 and license sli on a per board fee.
what else is new, there will be intel turbo cache2 pretty much, that will serve as a flash buffer/cache to your hard drives, which should improve hdd performance significantly, unless your running an sdd, in which case i doubt there will be much of a boost if any.
another thing is the uncore to memory multiplier limitation, wich will change. right now on i7 you have to run double the memory multiplier for the uncore, on i5 you will only have to run 1.5x the memory multiplier for uncore.
so that means with 4000Mhz uncore on i7 you are stuck to DDR3 2000, on i5 you can run DDR3 2666. that will probably still limit the best memory out there, but its better than i7 for sure, where you need subzero cooling to max out your memory clocks.
There will be i5 igp cpus with an igp northbridge under the hood, on the same package, but thats not really interesting for people here... the igp performance will be far from specatcular and the added heat doesnt help. another reason i dont recommend those cpus to xs readers is that they use QPI to connect the igp to the cpu, which will most likely limit overclocking.
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Originally Posted by saaya
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