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AMD FX-8150 Processor Review - Can Bulldozer Unearth an AMD Victory?

Author: Ryan Shrout
Subject: Processors
Manufacturer: AMD

Bulldozer Architecture (continued)

The below text was taken from Bulldozer at ISSCC 2011 - The Future of AMD Processors.

The second topic covered at ISSCC was that of “40-Entry unified Out-of-Order Scheduler and Integer Execution Unit for the AMD Bulldozer x86-64 Core”.  Single thread performance is still of great importance for modern processors, and this has been an area where AMD has lacked as compared to the competition.  The first work to help achieve better single thread performance was that of the fetch/prefetch, branch prediction, and decode.  AMD has still not covered those portions in depth, other than we know that a lot of work has been done to each individual unit.

Each integer unit has its own scheduler.  Each integer unit is comprised of two execution units, and then two address generation units.  The execution units are further divided so that one handles multiply and the other divide.   These are again newly designed units which have very little in common with previous processor architectures.

The schedulers have some very interesting wrinkles to them.  First off is the support for 40 entries, out of order scheduling.  It also supports up to 4 x 64 bit instructions in flight.  Michael Golden presented the paper, and his quote about the clock characteristics of these tightly knit units is as follows:

The out-of-order scheduler must efficiently pick up to four ready instructions for execution and wake up dependent instructions so that they may be picked in the next cycle. The execution units must compute results in a single cycle and forward them to dependent operations in the following cycle. All of this is required so that the module gives high architectural performance, measured in the number of instructions completed per cycle (IPC).

What is perhaps the most interesting aspect of these new designs is the use of standard cells vs. fully custom cells.  Place and route of standard cells can be automated, and it is relatively easy to create complex designs fairly quickly.  Custom cell layout is very complex and time consuming, but it has the advantage of being very efficient in terms of power consumption, and has a higher switching speed than standard cell designs.  Somehow AMD has taken a standard cell design utilized on GLOBALFOUNDRIES 32 nm SOI process, and made it perform at custom cell levels.  The integer execution units and the scheduler can run at the same 3.5 GHz+ speed as the rest of the chip, even though it has portions of the design made with standard cells.

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The full 8-core / 4-module Bulldozer Architecture found in AMD FX.

This apparently has allowed AMD to quickly and rapidly prototype these designs.  This has the advantage of being able to deliver to market faster than going with a fully custom part, and it also allows AMD to further test the performance and attributes of the standard cell design and possibly change it without the time and manpower constraints of custom cell.  How AMD has achieved this is beyond me.  Being able to implement standard cell design rules and achieve custom cell performance has been the holy grail of CPU/GPU design.  Obviously this has limitations, as the entire processor is not comprised of all standard cells.  I believe that Intel also utilizes some standard cell features in their latest series of processors, so AMD is not exactly alone here.

Power

Previous AMD processors were not designed from the ground up to implement complex and efficient power saving schemes.  Since Bulldozer is a new design altogether, the engineers are able to more effectively implement power saving into the processor.  Throughout the years we have seen small jumps forward from AMD with power saving techniques, but Bulldozer will be the first desktop/server product that will have a fully comprehensive suite of power saving technologies.

The CPU, in typical workloads (obviously does not include "Furmark" in SLI/Crossfire situations), takes up the majority of power in a system.  By being able to reduce a significant percentage of power draw at that one component will decrease the overall system draw to a great degree.

AMD now has fully gated power to the individual cores, which allows them to be completely turned off when not in use.  The replication of functional units (such as fetch and decode) for the individual cores also cuts down on the complexity, and thereby power draw, of the overall processor as compared to how many logical cores it has.  The clock grid (which provides the clock signals throughout the processor) also has been radically redesigned so as to be less of a power sink, and still be efficient in keeping the processor clicking along.

Clock gating, which turns off individual components such as execution units, has been much more thoroughly implemented.  There is something like 30,000 clock enables throughout the design, and it should allow an unprecedented amount of power savings (and heat reduction) even when the CPU is at high usage rates.  Even though a processor might be at 100% utilization, not all functional units are being used or need to be clocked.  By having a highly granular control over which units can be gated, overall TDP and heat production can be reduced dramatically even at high utilization rates.

AMD Turbo Core will also receive a great amount of attention.  The current Turbo Core we see in the X6 processors is somewhat underwhelming when we look at the overall complexity of AMD’s implementation.  For example, when three cores or less are being utilized on the X6 1090T, those cores will clock up to 3.6 GHz, while the other three go down to 800 MHz.  There is no real fine tuning of performance or TDP here, just an “on/off” switch for clocking half of the cores 400 MHz higher while downclocking the rest.  This is fairly basic as compared to Intel’s system.  Now it seems that AMD is implementing a system much like Intel’s.  We should see Turbo frequencies with differing numbers of cores which will be much more similar to what Intel offers with Sandy Bridge.

Due to the ground up design of Bulldozer, and the focus on decreasing power draw and heat production, we will see a nice reduction in power being utilized across the entire processor.

 

Bulldozer is a comprehensive blank sheet design which is very similar to the jump the company took going from the K5/K6 to the original Athlon.  AMD certainly hopes that it will be able to more adequately compete with Intel in terms of overall performance per watt, as well as die size and transistor count.  When the Phenom was originally detailed, many thought that it would prove to be the counter to the Core 2 that AMD needed, but unfortunately that design was not forward thinking enough in terms of design to adequately compete.  Up through the current generation of parts, Intel was able to use fewer transistors and a smaller die size to create products that were significantly faster than what AMD was able to provide.

October 11, 2011 | 10:07 PM - Posted by ZackJ (not verified)

Another great article Mr Shrout. I really appreciate the honesty you provide in your assessment of this processor. Hearing different things on the web I was very interested in this processor. Great new design for the future but it just doesnt seem to compete as well as I would like. I currently have a AMD Phenom II X4 965 and this review has me not really wanting to upgrade to it. I plan to get a new mobo and ddr3 ram so looks like that and a new vid card will be my only purchase in the near future. Although given this review would u recommend the FX-8150 or Phenom X6 1090T/1100T?

October 12, 2011 | 07:24 AM - Posted by Ryan Shrout

It is hard to deny the value of the X6 processors now based on their price. If money is kind of tight, I have no qualms recommend the 1100T.

November 8, 2011 | 04:55 AM - Posted by drbaltazar (not verified)

Ryan and his crew please stop doing bogus article on fx 8150.unless amd or someone at ms or linux has some benchmark that test with fx feature in mind all test will be irelevent.fma4 alone isnt supported and you try to compare actual fma proc .intel. vs fx.comparing a cpugpu vs a cpu?core parking activated?threading issue in window?mobo bios issue that wont be fixed in w8.come on just stop benchmarking this cpu give a call to mobo.ms.amd then when they have fixes you can revisit[about6 month worth]some silly test seams to forget one fact very important here in 2 year intel will have fma4.2 year.amd isso far ahead they cant even speak to any one for fear of copying.it isnt they dont want to.the techno is just plain further ahead then all expected.people wonder why fx is selling like hotcake.when was the last time you had a 2 year in the futurtechno avail today?it rarelly happen .this is huge new for corp in the software business be it gaming or anything else.i bet a lot are hard at work opimising .or trying.for fma4 and all other lessb highlighted feature.but like i mention this proc was released 6 month too early

October 11, 2011 | 10:18 PM - Posted by dreamer77dd

I wonder what Trinity will be like. hmmm

October 11, 2011 | 11:18 PM - Posted by player-x

Nice article only the tables are hard to readout :(

I understand the dilemma of sorting by name or rank.

But personally i really prefer ordering by rank, but that's me.

A great solution would be to have mouse-over change the ordering so everyone can pick whats best for them.

Next to that some color coding would be nice of competing products
Light Blue for i5 2400 blue for 2500K and dark blue for 2600K
next to that dark green for the FX green for the X6 light green for the X4.

To just suggest something.

Like a said, good read, so so tables

October 12, 2011 | 07:26 AM - Posted by Ryan Shrout

Yeah, that's fair. We'll see what we can do to improve that in the future!

October 11, 2011 | 11:27 PM - Posted by Yangorang (not verified)

It's interesting to note that you guys came to a rather different conclusion than Anandtech did with regards to gaming performance with Bulldozer.

http://www.anandtech.com/show/4955/the-bulldozer-review-amd-fx8150-tested/8

I'd definitely like to see some more testing done on this.

October 12, 2011 | 07:30 AM - Posted by Ryan Shrout

Notice they ran their games at resolutions like 1024x768 and at the highest, 1680x1050 while I ran my tests at 1080p. In truth, the higher the resolution the less important the CPU performance tends to be.

To some people, they just want to know the raw gaming power of the CPU so running at low resolutions, sometimes even lower than is likely to be run by the gamer (who plays games at 1024x768 anymore??) will show the biggest differences.

In my case I thought it more pertinent to show the most "real world" cases and 1080p seemed to be the way to go.

October 12, 2011 | 07:07 PM - Posted by Jeremy Hellstrom

You can't argue the Civ V findings, but [H]ard|OCP used similar resolutions and found similar results to Ryan's.

http://www.hardocp.com/article/2011/10/11/amd_bulldozer_fx8150_gameplay_...

October 12, 2011 | 12:36 AM - Posted by Bamstick (not verified)

I would to see more gaming benchmarks. Having only 2 games on there seems lazy to me. Where is Starcraft 2, Bad Company 2, Rage, The Witcher 2, and heck put World of Warcraft on there, you know games that people actually play. I don't anyone who plays Lost Planet 2.

October 12, 2011 | 12:37 AM - Posted by Bamstick (not verified)

Oh and of course Crysis, Crysis Warhead, Crysis 2. Come on!

October 12, 2011 | 05:28 AM - Posted by gwaland (not verified)

Did I miss in the article where you explained why you used a 1090t instead of the top of the line 1100t for most of your benchmarks?

October 12, 2011 | 07:34 AM - Posted by Ryan Shrout

Ah, good point. We used the 1090T results from a previous article (Llano I think) and didn't have time to get in the 1100T to run the full allotment of tests before publication. Instead, with our time we had, I was able to run the 1100T through some our architectural analysis tests (core scaling, etc) and gaming.

October 12, 2011 | 05:55 AM - Posted by Anonymous (not verified)

So... how well does this CPU FOLD????

WOndering if it can handle bigadv folding...

October 12, 2011 | 07:09 PM - Posted by Jeremy Hellstrom

You ain't the only one! I suggested it to Ryan but he hasn't done it since the PS3. Mind you I'm a BOINCer myself.

October 12, 2011 | 06:24 AM - Posted by krankycheese

Based on this review, it's hard to justify upgrading from my Phenom II 955 especially when my PC is used mostly for gaming. I was hoping for better power consumption numbers when compared to what Sandybridge has.

The architecture is intriguing and has potential. It will be interesting to see what AMD comes out with the next iteration.

October 12, 2011 | 06:33 AM - Posted by bjv2370

ill wait for piledriver for improvements...

October 12, 2011 | 06:42 AM - Posted by Anonymous (not verified)

I just finished reading all 3 reviews( Anand, Toms and PCPER) and just like Yangorang said, WTF?!

The test show some consistencies but there is still a rather big difference in attitude and benches towards the 8150FX.

I think there is a bit of Fanboy-ism being implemeneted by ANAND and TOMS ( you can see by the comments as well) review. Granted it may not be a 2600k but its gets pretty close between a i5 and the i7 so I feel that those 2 reviews excerted much more biased in their writing towards the intel chip, even when the BD came close.

There are some crazy things like the power usage, but really? Most of the people posting dont really care about their lightbill( multi gpu, plethora of fans and 1100watt PSUs) so why are people complaining that much?

I already bought me ASUS CH-V 990fx mobo yesterday, and my AMDHD5970 (2gb) so I think I will just push on through with the BD. My last build was a core 2 duo so I thing I will be good non the less.

October 12, 2011 | 07:37 AM - Posted by Ryan Shrout

I don't think it is a BAD processor necessarily, but I find it hard to recommend the FX-8150 over the Core i5-2500k or even the i7-2600k if you are building a new system from scratch.

You have a 990FX Bulldozer-ready motherboard and want to get rid of that older CPU? Sure, the AMD FX will improve your system somewhat.

As I mentioned in my conclusion page, the primary issue is AMD thinks its processors are worth more money they probably are for MOST work loads.

October 12, 2011 | 09:22 AM - Posted by Anonymous (not verified)

Thanks for the review Ryan. I bought a Core i5-2500K and z68 mobo 2 weeks ago, and I'm not regretting my purchase one bit. We'll have to see if that sentiment persists thru to when Ivy Bridge comes out. :P

October 12, 2011 | 07:44 AM - Posted by Rion (not verified)

No wonder AMD is attempting to get pile-driver out as soon as possible, they probably knew bulldozer wasn't going to light the world on fire. Now the question is do you wait for Trinity/pile-driver and FM2. Somehow I think most people will wait, unless they already bought the AM3+ board. Isn't Pile-driver and FM2 by Q2 2012?

October 12, 2011 | 07:47 AM - Posted by Irishgamer01

OH Dear,
Doesn't even look as if its worth updating from an X6.
Hope the 7000 cards are good cause AMD could be in trouble.

October 12, 2011 | 07:57 AM - Posted by Nebulis01

Ryan,

Thanks for including an older intel proc (the Q9650) I have a QX9650 and I've been looking to upgrade and was hoping to head back to AMD with this Bulldozer release. Sadly I see a i7-2600 in my future.

Thank you as always for the great review!

October 12, 2011 | 09:46 AM - Posted by Ryan Shrout

Thanks for reading!

October 12, 2011 | 08:58 AM - Posted by pdjblum

Thorough, comprehensive, objective, and very informative review. Well done.

October 12, 2011 | 09:51 AM - Posted by Steven (not verified)

Well this make me wish I hadn't already bought it, since I have an 1100t... So much anticipation, and I suppose I'm about to be let down.

October 12, 2011 | 10:47 AM - Posted by Bill (not verified)

I couldn't care less where AMD goes from here in their lineup. I'm done waiting for their next "fast" cpu, which is only going to be a pathetic 10-15% improvement anyway. I'll have a 2500k under my hood now, and AMD will unfortunately be in my rear view, broken down on the side of the road overheating.

October 12, 2011 | 11:16 AM - Posted by Oskars (not verified)

What is the deal with the performance?
Doesn't it look strange that a 2 billion transistor chip (fx-1850) is a tad slower than a 0.9 billion chip (i7 2600k) of witch 1/4 is a gpu.
There are a few major improvements, but still.
Is that just an unpopular code or a task sheduler comunication mishap? Some people speak of imprvements in windows 8.
Could that be it? That Bulldozer is a year early, and not late at all?

October 12, 2011 | 12:19 PM - Posted by hechacker1 (not verified)

Indeed. It seems ridiculous that 2 billion transistors nets them a slightly slower chip than even their last generation.

It doesn't make sense. I think AMD needs hyper threading bolted on to extract more performance or something. All those transistors are going wasted, or it's just insanely inefficient.

October 12, 2011 | 12:42 PM - Posted by Ryan Shrout

The module design was to be AMD's take on HyperThreading but better.

Yes, Windows 8 will help some, but even in AMD's best case scenarios we are talking 4-10% improvement there.

In reality, we are just as confused how 2 billion transistors loses to 1.16 billion transistors this regularly.

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