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Does PCIe3 make Bulldozer obsolete before it's out?

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October 5, 2011 6:20:39 PM

I have been waiting and waiting for Bulldozer to come out and decide what processor to buy a new PC (for months). Now that it's about to come out, I have a major concern about its potential value even if it's performance/$ beats Sandybridge because of pcie3 and ivy bridge compatle motherboards available now.

2 options:
1. buy i52500k and overclock, with a pcie3 supported motherboard that will also support ivy bridge coming out next year (able to cpu upgrade to new die shrink, though probably not the next architecture "tock").

2. buy bulldozer CPU with potentially better performance/$, but I have the impression it will not support pcie3, since there are no AM3+ boards on the market right now with it? Also I can't find confirmation, but I have the impression that the die shrink of bulldozer will not be supported with AM3+ boards, so there's no cpu upgrade path?

If my understanding is correct, then even if you get the same performance of sandybridge for $50 less with bulldozer, you will have no next generation CPU upgrade path, nor will you have any pcie3 support (bandwidth is not needed yet, but potential to max out pcie2 bandwidth using ivy bridge could arguably be achieved).

Have I been waiting all this time for no reason? I'd love to hear opinions of the well educated people of this site.
thanks.
a c 850 à CPUs
October 5, 2011 6:45:58 PM

Sandy, Bulldozer and probably some future generations of CPU's will be obsolete before we have fully utilized PCIe3. At the current we are just starting to exceed PCIe1.
a c 141 à CPUs
October 5, 2011 8:45:00 PM

Your waiting for nothing. Even if they released IVY tomorrow you have nothing to plug into your pcie3 slots. Video card currently run almost as good on an x8 link as on an x16 which is what pci3 is bringing to the table - about 2 times more bandwidth that nothing short of raided ssd on pcie come close to being able to saturate. your video card certainly cant.
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October 5, 2011 8:52:32 PM

I thought I read somewhere that bulldozer is going to be supported on am3+ with bios updates?
a b à CPUs
October 5, 2011 8:54:58 PM

popatim said:
Your waiting for nothing. Even if they released IVY tomorrow you have nothing to plug into your pcie3 slots. Video card currently run almost as good on an x8 link as on an x16 which is what pci3 is bringing to the table - about 2 times more bandwidth that nothing short of raided ssd on pcie come close to being able to saturate. your video card certainly cant.

Great post.
And yes we have just broken the pcie bandwidth though it remains to be seen that high end cards only have this.
October 5, 2011 9:56:04 PM

NO...
a c 82 à CPUs
October 5, 2011 10:16:38 PM

if you want high performance in games then you want to go intel anyway, Bulldozer has more cores but no game out will make good use of more than 4 cores, so if you got an 8 core bulldozer, a lot is going to waste, and preliminary benches show slower per core performance than Intel SB.
a b à CPUs
October 5, 2011 10:22:30 PM

iam2thecrowe said:
if you want high performance in games then you want to go intel anyway, Bulldozer has more cores but no game out will make good use of more than 4 cores, so if you got an 8 core bulldozer, a lot is going to waste, and preliminary benches show slower per core performance than Intel SB.

I personally wouldnt mind 8 cores but if they are eight slow cores then its not likely attracting alot of attention..
October 7, 2011 2:13:15 PM

AMD's next generation of video cards (7000 series) are coming out Q1 2012 as I understand it, and they will be the first generation of pcie3 cards. There is also new RAM coming on the high end boards from RAMBUS technology that's supposed to be over 2x the bandwidth of GDDR5. I think it's reasonable to assume that pcie2 will be a requirement to realize the full potential of these cards coming out very shortly. So, PCIe2 is already a requirement for me buying a computer today obviously, unless I never want to upgrade. there's no point in discussing the fact that pcie1 is not currently fully saturated except with extreme current generation cards.

I realize this is an assumption, but I find it reasonable to assume that bulldozer will have better performance/$ for mid-range and low-end processors. I'm a mid-range enthusiast looking for value, so typically AMD appeals to me.

Now let's think about my next upgrade in 3 years (without having to buy a new motherboard) :

AMD: buy an AM3+ board with a bulldozer processor now, with pcie2.

pros: new AMD architecture, probably better performance/$ than sandybridge

cons: next generation of bulldozer (die shrink only) will not fit in AM3+ I think?, so can't upgrade CPU.
video card 3 years from now will be maybe the AMD 9000 series, the 3rd generation of pcie3 cards. I'd be putting these into a pcie2 slot. Now I could be bottlenecked by EITHER the (non-upgradeable) bulldozer CPU from 3 years ago, OR the pcie2 interface.

Intel: buy sandybridge now with pcie3 support motherboard, which supports ivy bridge released next year

pros: 3 years from now I can buy an ivy bridge processor as an upgrade, and a pcie3 video card (let's assume the same AMD 9000 series card from above). Now I know the pcie2 interface can't be a potential bottleneck (becuause my 3 year old mobo has pcie3), and my processor can be upgraded to something better also.

cons: less performance/$ (probably) than bulldozer, and I'll have less speed with video encoding for those 3 years, and don't get to support my favored company (AMD).

Am I missing anything? I hate to say it, because i really would rather buy AMD, but it seems like I'd be severely limiting my upgrade options (without having to buy a new motherboard).
a b à CPUs
October 7, 2011 2:31:32 PM

Oct 12th looks like a very real (although not official) release date for Bulldozer. Why not wait and see where it actually stacks up against SB?

The HD7000's XDR2 has 2x the bandwidth but thats from card memory to GPU - it never leaves the card through the PCIe slot, so PCIe 3.0 will only effect the 79xx (if any). You will probably be happier with Bulldozers encoding performance.
a b à CPUs
October 7, 2011 10:58:40 PM

I wouldn't expect AMD chips to be on a new process in 3 years. It took about that long for them (at the time, now GloFo/TSMC) to get from 45 to 32, and it's not going to get any easier.

That aside, if you plan to upgrade in ~3 years you'll be getting a new mobo for DDR4 anyway. I also rarely upgrade (just replaced my athlon64 this summer) and unless you upgrade every year, just understand that roadmaps will change far beyond your planning horizon.
October 8, 2011 3:29:02 PM

torque79 said:

cons: next generation of bulldozer (die shrink only) will not fit in AM3+ I think?, so can't upgrade CPU.
video card 3 years from now will be maybe the AMD 9000 series, the 3rd generation of pcie3 cards. I'd be putting these into a pcie2 slot. Now I could be bottlenecked by EITHER the (non-upgradeable) bulldozer CPU from 3 years ago, OR the pcie2 interface.

the generation of processors coming out after bulldozer is called Piledriver and amd has shared several details about it.
it will use am3+ socket if you have the 990fx northbridge. i dont know why its just that one northbridge.

it will not just be a die shrink. infact its not supossed to be a die shrink at all. should be 32nm. amd wants to copy intels tick tock method of releasing processors.
tick = use smaller process.... tock = modify architecture. repeating.

Piledriver while based on bulldozer is improved to allow for more instructions per clock(IPC). no info on how much, though 10% at best

piledriver will support PCI-E 3. though the current motherboards dont. but unless video cards get more than twice as powerful in the next 3 years your demands are met. and they wont get that powerful. we will be lucky to get 60% more in 3 years.

overall performance gains with piledriver will be about 10%. though this is little you know the cost of the processor will be low. and is scheduled for Q3 2012, just a year after bulldozer isnt bad for 10%. the i7 2600 came out two years after i bought my i7 950 and it isnt 10% better. and it has an xtra 240MHz over my 950.

AMD will use a new version of the turbo core, no details of how well it works.

Piledriver will support two new instruction sets, FMA3 and something it calls Converged BMI (Bit Manipulation Instructions).

thats all i can remember.

October 11, 2011 1:15:25 PM

Thank you so much for your replies everyone. It's good to hear piledriver will be supported on AM3+ for a while. pcie3 had me paranoid because I made a bad decision before choosing AGP and an older AMD slot for a new pc when pcie was just coming out to save a couple hundred dollars. then pcie went beyond what AGP could provide, and I could no longer upgrade video to keep from my video card being the bottleneck. I am just trying to ensure I am not doing the same thing again.
a b à CPUs
October 11, 2011 2:30:47 PM

PCIe 2.0 -> PCIe 3.0 is an entirely different story than AGP -> PCIe; ALL PCIe x16 slots are backwards/forwards compatible, its just a bandwidth difference.

The GPU's processing power is still the bottleneck on PCIe 1.0, NOT the PCIe interface (in most cases). By the time you need PCIe 3 you will also need a new motherboard for socket/memory/sata/usb changes...
October 11, 2011 3:23:44 PM

I understand your question and demands. I for one am the same. I know that we are far from reaching PCIe 2.0, yet, it would be sweet to see PCIe 3.0 capable just so I can upgrade later and at the very least still have a feeling that I can fully utilize a graphic card.

Perception and reality and two strong motivators that result in self defining near future computer components ability and capability.
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