Is the i7 860 a rival to the i7 920? Discuss!

[Zenduri]

I've been sitting on the fence now watching the progression of the newer Intel I7's e.g Bloomfield and Lynnfield.

Its accepted that the 920 is a formidable chip pushing the 4-4.5ghz boundries on decent cooling and its one of the main reasons why such a chip has become so popular.

With the release of the new i7's on the lynnfield skt im starting to think theres a real contender to the 920's throne.
While the 1156 skt is a new tech and the 860 now being adopted by more users theres some interesting results popping up.

The 860 is now starting to be thoroughly tweaked and tested and results are springing up now showing that its clocking just about as well as the 920.

I know im looking forward to the i7 860s with a even further reduced TDP and hopefully a tweaked revision.

The 860 seems to hi 3.8ghz very easily so im only including examples above 3.8ghz

Half Way down semi stable 4.4ghz on air
4.6ghz unconfirmed stability
4.4ghz but with HT off
4.2ghz with HT

Whats your thoughts and opinions?

 

[cmndr_andi]

The i7 860 is definitely a rival to the i7 920. They overclock very similarly and they perform identically when clocked to the same speed.

The i7 860 is a bit more expensive than the i7 920 at the minute. You could argue that motherboards for the 920 are more expensive - which is generally true. However, all of the X58 boards, even the cheapest ones support x16x16 crossfire (SLI as well for some) and Triple channel DDR3 and all seem to happliy overclock the i7 to 4GHz and beyond.

With this in mind, i'm still of the opinion that the p55 platform is ideal for the i5 - a really nippy, good value chip. But the i7 is still best on the X58, its a bit more expensive but it has a few better features which help to tip the dead-heat.

That all said, if Lucid Hydra is P55 only then ignore all this and buy an i7 860. However, I don't expect this is likely.

 

[Zenduri]

I know this is a silly question but would the lynnfield chips have the ability to run triple channel memory or are they purely limited to dual?

It would be nice to see a revision of the lynnfield chips with x16/x16 even if its the i7 lynnfields, if that happened i really think lynnfield would fly off the shelves.

 

[cmndr_andi]

The i7 860 is dual channel only, here is the intel page on it- it shows the number of memory channels as two. Therefore you would need a whole new chip (and platform) to run triple channel, ie the 920/ X58.

I believe the PCIE channels are governed solely by the motherboard, so intel would have to change the P55 chipset to support 32 PCIE 2.0 lanes. I don't see them doing this as it would cannibalise their X58 market.

 

[Zenduri]

Well it makes sense re the memory but i thought that the PCi-e lanes were limited by the CPU onboard graphics controller.

Also the x58 will still remain for the enthusiast market, if they changes the lynnfield capability to 32 pci-e lanes. It would make sense to allow 32 lanes on a mainstream processor and board.

 

[cmndr_andi]

I just remembered the EVGA P55 classified. It has much more PCIE lanes than normal P55 boards as it uses an nf200 chip to add some.

Normal p55 boards are limited by the p55 chip, not the CPU, in terms of PCIE lanes.

 

[Zenduri]

Hmm fair enough I learnt something new. I thought there was a limit imposed somewhere along the line by the cpu graphics controller.

 

[mdjmcnally]

ALL P55 based motherboards still only have a 16 PCI-E lane connection limit of the CPU to the PCI-Ex16 slots on board.

All lynnfield chips have the connection straight into the CPU itself for PCI-E x16, not into the P55. The P55 chipset providing 4 x PCI-E lanes for the additional PCI-E slots on board.

This is a limit of the CPU itself, and has NOTHING todo with the chipset, and will have nothing to do with onboard GPU as the current lynnfields don't have one.

P55 motherboards with an nf200 chip such as the EVGA FTW200 etc have 16 lanes from the CPU to the nf200, then 32 lanes from the nf200, 16 each to a pair of PCI-Ex16 slots or broken down as 4 x PCI-Ex8. There is still only 16 lanes into the CPU.

The main difference between i5 and i7 on 1156 is that the i7 has multithreading, ie 4 cores, 8 threads on i7 as opposed to 4 cores 4 threads on the i5.

 

[cmndr_andi]

ALL P55 based motherboards still only have a 16 PCI-E lane connection limit of the CPU to the PCI-Ex16 slots on board.

All lynnfield chips have the connection straight into the CPU itself for PCI-E x16, not into the P55. The P55 chipset providing 4 x PCI-E lanes for the additional PCI-E slots on board.

This is a limit of the CPU itself, and has NOTHING todo with the chipset, and will have nothing to do with onboard GPU as the current lynnfields don't have one.

P55 motherboards with an nf200 chip such as the EVGA FTW200 etc have 16 lanes from the CPU to the nf200, then 32 lanes from the nf200, 16 each to a pair of PCI-Ex16 slots or broken down as 4 x PCI-Ex8. There is still only 16 lanes into the CPU.

The main difference between i5 and i7 on 1156 is that the i7 has multithreading, ie 4 cores, 8 threads on i7 as opposed to 4 cores 4 threads on the i5.

You are quite right, apologies for my ignorance - I must have got confused with the X58 method which is so different.

These are the diagrams I found helpful.

Clearly, if you want to use a bunch of graphics cards, get the X58.

 

[feeddagoat]

I believe the PCIE channels are governed solely by the motherboard, so intel would have to change the P55 chipset to support 32 PCIE 2.0 lanes. I don't see them doing this as it would cannibalise their X58 market.

At the end of the day if the mobo manufacturers find a hack or a way of running x58 chipset with LGA1156, theres no stopping them producing boards with 16/16 PCI lanes. Unless intel has something in the licencing agreement. Just look at the bios for unlocking AMD cores.

 

[Zenduri]

Its good that we've got some clarification on the chip arcitecture as obviously not everyone undestands myself included.

But what do you guys think performance wise compared to the 920. After all the pci-e lane issues will only really effect 5-7 fps in dual card setups. (As shown in benchmaks of the 5870 in crossfire)

 

[feeddagoat]

custompc mag/bit-tech where showing slightly higher averages with the 920 but the mins where about 20-30 fps higher. They tested L4D, crysis and STALKER @ 1050 (22" native res) with 2 or 4 AA. Seems stupid they didn't test up to 1600, or didn't print the results in the mag. I think they where trying to prove the difference between LGA775 and LGA1156 rather than LGA1156 over 1366. Aren't lower resalutions CPU bound anyway?

 

[HazardO]

Clearly, if you want to use a bunch of graphics cards, get the X58.

TBH my take on the benchmarks I've seen, the Lynnfields's 2x PCIe2 x8 is enough for any current dual single GPU card solution (Including the HD5870 in crossfire). The difference is ~2% or less in performance.
Certainly it's a fail for 3 way SLI or crossfire though, and it might start to show it's weaknesses with a pair of GTX295s or a pair of HD5870x2s.
I certainly wouldn't say Lynnfield is poor for SLI, but it's clear that the x58 platform has more to give in multi GPU setups.

 

[Stormar]

TBH my take on the benchmarks I've seen, the Lynnfields's 2x PCIe2 x8 is enough for any current dual single GPU card solution (Including the HD5870 in crossfire). The difference is ~2% or less in performance.
Certainly it's a fail for 3 way SLI or crossfire though, and it might start to show it's weaknesses with a pair of GTX295s or a pair of HD5870x2s.
I certainly wouldn't say Lynnfield is poor for SLI, but it's clear that the x58 platform has more to give in multi GPU setups.

and how many actullay will or can afford to go down that route 1 dual or 2 in sli/crossfire is more than enough really

 

[mmj_uk]

At the end of the day if the mobo manufacturers find a hack or a way of running x58 chipset with LGA1156, theres no stopping them producing boards with 16/16 PCI lanes. Unless intel has something in the licencing agreement. Just look at the bios for unlocking AMD cores.

What would be the point? the whole idea behind the LGA1156 platform is that it's a cheaper alternative to buying an X58.

 

[Typhoon]

There only a £30-40 differance in it between and 860 and 920 setup anyway.

 

[fizzle-187]

I have an 860 and it's an AMAZING chip. I wouldn't change it for the world. Extremely fast and very smoooooth!



EDIT- I can't wait till I overclock the BEAST as well, even MORE SPEED!

 

[feeddagoat]

What would be the point? the whole idea behind the LGA1156 platform is that it's a cheaper alternative to buying an X58.

When the 920 and 940 is discontinued tho your looking at £300+ more for LGA1356 processors alone. You missed my point tho that intel may produce the chipset but theres nothing to stop manufactures bringing x16/x16 to LGA1156 unless Intel have some legal document to stop them. In which case I donno if such thing exsists

 

[HazardO]

When the 920 and 940 is discontinued tho your looking at £300+ more for LGA1356 processors alone. You missed my point tho that intel may produce the chipset but theres nothing to stop manufactures bringing x16/x16 to LGA1156 unless Intel have some legal document to stop them. In which case I donno if such thing exsists

There is one problem with this, how would provide the bandwidth between the added PCIe lanes and the CPU? Lynnfield uses a DMI interface not quickpath to connect to the northbridge, and it may not have enough spare bandwidth to bunnyhop even a single 16way PCIe slot's requirements over it.

The x58 chipset has the massive bandwidth of the quickpath connect, that way the CPU has access to the PCIe lanes, Lynnfield has it's own PCIe lanes and a seperate DMI bus

 

[mmj_uk]

There is one problem with this, how would provide the bandwidth between the added PCIe lanes and the CPU? Lynnfield uses a DMI interface not quickpath to connect to the northbridge, and it may not have enough spare bandwidth to bunnyhop even a single 16way PCIe slot's requirements over it.

The x58 chipset has the massive bandwidth of the quickpath connect, that way the CPU has access to the PCIe lanes, Lynnfield has it's own PCIe lanes and a seperate DMI bus

Indeed, just looking at the graphs above the LGA1156 CPU's would have to connect to the X58 northbridge via its 2GB/s DMI bus (QPI = 25GB/s) and the southbridge would also be sharing that same bandwidth.

In the end you'd get a catastrophic bottleneck on the PCI-E bus compared to just using the onboard LGA 1156 PCI-E controller (16GB/s), to make it work they would need to modify the CPU to be the same as a 920 (with QPI) which defeats the point entirely.