They're lower-end processors; obviously they'll have less cache. This has been standard practice since L2 and L3 cache were included on CPUs.ronch wrote:1. I was kinda surprised to see that the FX-4130 and FX-4300 have only 4MB of L3 cache. I used to think 8MB is standard on all their FX chips. A quick look at CPU-World also indicates 4MB of L3 for the FX-4300. Ok, perhaps they're having higher L3 defect rates than expected on those quads.
Piledriver CPUs have 64Kbytes L1 I-cache that is shared across the module. Each ALU in the module has 32Kbytes of D-cache. Thus, 64KB + 64KB per module. Piledriver has double the L1 D-cache per ALU versus Bulldozer.ronch wrote:2. The trickiest part where AMD always seems to have trouble is cache sizes, since they, in the past, seem to get things mixed up a little bit. For example, I remember seeing tables on their site indicating L2 cache for the Phenom II to be 512KB, but it didn't say whether it was just for one core or all the cores. They've fixed it now, though. But look at the FX table, specifically, 'L1 Cache (Instruction + Data) per core'. It says each core has '128KB (64KB + 64KB)'. That's a bit off, isn't it? There's 64KB of L1I per module, shared by two cores, and each core gets its own 16KB of L1D. Perhaps you can split the 64KB into two and say each core gets 32KB L1I and 16KB L1D, for a total of 48KB. Not clean cut, but at least you have a better sense of what's in there. However, it's not 64KB + 64KB like the table says.
HT has never made a great amount of sense to me, but CPU-Z could also be reporting incorrectly. Not sure on this one.ronch wrote:3. It says HyperTransport runs at 4GT/sec., or 16GB/sec. A quick check with CPU-Z, however, tells me my FX-8350's HT runs at 5.2GT/sec, not 4.0GT/sec. Not sure if AMD is being conservative here or if my MSI 990FXA-GD65 is pushing my HT beyond spec, but if some of their models run HT at 4.0GT, they should've at least indicated it the way they indicated that different models have different L3 cache sizes.
The FX-4130 also had 4mbytes. I don't find it that unusual. Maybe the larger L3 isn't of benefit with only two modules, or is of minimal benefit. Or, maybe they're having yield issues. I don't find it terribly likely since 32nm is quite mature, however.ronch wrote:Yes, I understand that lower end CPUs tend to have less resources, particularly cache. I was just a little bit surprised to learn that the FX-4300 has just 4MB of L3. The FX-4100 had 8MB of L3, and so did the FX-6100. 8MB L3 was standard with Zambezi. L2 cache gets lopped off everytime AMD turns off a module, but L3 pretty much has remained intact back with Zambezi. So with Vishera, things have changed quite a bit, which is kinda disappointing. Since all Vishera chips are the same, it wouldn't make sense for AMD to turn off parts of the L3 on a whim unless they're having yield issues. Product differentiation? Nah. Just look at Zambezi.
No, per AMD's charts I do believe Vishera has double the L1 D-cache from Zambezi. The only sources I can find on this (google vishera double L1) all talk specifically about doubling the Translation Lookaside Buffer, but I believe that resides in the D-cache, so there you go.ronch wrote:As for the L1 caches, I understand that each module shares 64KB of L1 Instruction cache. Each 'core' (or integer cluster) has its own 16KB of L1 Data cache. Under CPU-Z L1 Data is listed as 16KB x 8, L1 Instruction is listed as 64KB x 4. IIRC Bulldozer presentations also indicate this. Cache sizes remain untouched from Zambezi to Vishera, I reckon.
I find this likely as well.ronch wrote:Bensam, I think it's not unlikely that current Zambezi-based products are old stock. Isn't this similar to Llano where AMD currently still has warehouses full of them because OEMs don't want them because Trinity is better and everyone wants it? I think AMD is finding it hard to sell all its Zambezi chips.
Depends on what you're doing! I'd sure rather have the i3, since I mostly play games. First-gen FX is AWFUL at games.Bensam123 wrote:I really wish TR would update their price comparisons every few months like they were doing with hard driver prices after the floods. A 8120 for the same price as a i3 is pretty killer.
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