7950 or 670?

[Shmee]

Certainly seems to be a good card then, but not a whole lot of OC headroom in there review. While a great bargain @ stock comparisons, the OCd 7950 still competes if not beats the 680, not to mention 670. Obviously YMMV.

 

[zaydq]

Just thought I'd let ya know I overclocked my msi 7950 twin frozr to 1200 core clock and 1600 memory stable. A 7950, at the price they're going for, wipes the floor with nvidia's gtx 670 and 680

 

[SheHateMe]

Just thought I'd let ya know I overclocked my msi 7950 twin frozr to 1200 core clock and 1600 memory stable. A 7950, at the price they're going for, wipes the floor with nvidia's gtx 670 and 680

Wow. Did you use MSI Afterburner to do that?

 

[Shmee]

most likely that or sapphire trixx. AMD overdrive in CCC can also be used.

 

[lopri]

I've been testing ASUS DirectCU 670 TOP and Gigabyte WindForce HD 7950. Both are fantastic cards and in my opinoin and it is a tangible upgrade from my previous GTX 580. Being custom-designed, both the 670 and 7950 have had zero problem with heat or noise. (except that the first 7950 had a faulty fan making clicking noise, which I promptly replaced with a new one)

I give a slight nod to the 670 because it fixed many of the shortcomings of previous Geforce products. 7950 feels more incremental improvements compared to previous AMD products, despite its significant architectural departure. The 670 is a very refreshing product in that it overcomes a whole swath of negatives of the Geforce products of the past.

The ASUS 670 TOP is at its limit and I haven't had any luck with overclocking. But it already clocks at 1240~1250 MHz with firm stability and that's more than what I hoped for. But I did overclock its memory to 1700 MHz, which was also completely stable. Very satisfying experience.

The Gigabyte 7950 was very satisfactory as well. Incredible cooling performance. (~55C top when overclocked, and looping Heaven benchmark for 5 hours) I had some trouble with overclocking initially, but soon found out that it's because, upon resume from S3, the voltage overclock I set in Afterburner did not hold. I had to manually set voltages upon every wake-up in order to keep the overclock, which is a chore with very little reward.

So for the 7950 I ended up with 1050/1500 which is the max it'd do without touching the voltage. For Benchmark purposes I could crank it up to 1150/1500 @1.175V for the core. (Its default 3D voltage is 1.050V)

Performance is nearly identical between them but there is one not-so-insignificant shortcoming of the 7950. The 2D frequency takes priority over the 3D frequency when there are tasks competing for the GPU resources. For example, if you watch a YouTube video while playing a game, the clock speed defaults to that of 2D frequency. The 670 doesn't exhibit this behavior and handles multitasking and task-switching more graciously than the HD 7950, which may be attributed to its new memory controller and dynamic voltage/frequencies. (Thank you, Cookie master for pointing it out and I now can also vouch for it)

As for the on-board memory, I can't decide my mind. On the one hand, 2GB of the GTX 670 does feel somewhat limiting (I mean, StarCratft II @2560x1600 consumes 1.6 GB+ with 4AA according to GPU-Z). With many applications turning to GPU for its performance, I do feel like 2GB of onboard memory will be cutting it close in near future. And I don't think a 4GB version is going to help much for the 670, unless memory bandwidth also increases with faster memory. On the other hand, I am rather skeptical of HD 7950's 3GB becoming handy in anytime soon, considering its rather lackluster multi-tasking performance compared to GTX 670. (Not sure its latching onto 2D frequency is hardware-oriented or drivers-dependent)

Still that doesn't mean I did not enjoy HD 7950 a lot. As soon as I swapped out the 670 for the 7950, I was greeted with the warm/saturated/vibrant/accurate colors that I had grown to expect from AMD products. (The 670 still retains its bleached color tone that has been bugging me on the previous NV cards - and no, you cannot exactly rectify that with calibrations) Also there was zero driver issues I experienced under normal usage. Only time where drivers acted weird was when voltage overclocking was involved, and I knew what I was doing wrong.

Interestingly, the so-called "power limit" slider thing helped neither the GTX 670 nor the HD 7950. Both cards either recovered or hard locked when I tried to overclock just 25 Mhz more by setting the slider at +20%. So I am leaving it to 0% for both.

I spent $320 for the 7950 and $380 for the 670, and have no regrets so far. Often times there usually a winner in my subjective judgment and I end up selling one over the other, but this time I am not sure about that. But it's been only a week so I shall see.

Only games I have at handy for this brief testing: StarCraft II, The Witcher 2, and Crysis/Oblivion. Almost identical performances throughout between these two cards. Advantage the 670, enabling Ambient Occlusion in SC2 via driers which I kind of like. Advantage the 7950, for the Witcher 2 with faster menu/interface navigation.

 

[guskline]

Very thorough analysis lopri.

 

[ShintaiDK]

Lopri, you cant measure VRAM that way. You need to use process explorer.

 

[zaydq]

I used msi afterburner for my 1200/1600 oc. Its stable in gaming and 3dmark11 but overheats in heaven. I. Used asus gpu tweak to unlock frequencies. I currently run 1100/1350 for everyday gaming and use as it runs no higher than 66 degrees under load. 1200/1600 was stable in heaven with high fan speeds but unbearable to listen to. The msi 7950 is built on a 7970 pcb which I attribute the great oc potential to.

 

[cmdrdredd]

Lopri the slider for tdp on the gtx 670 wont affect clock speeds you can obtain via overclocking since you are raising the base clock too. What it does affect is the max boost clock you might see in your games under load. For example I set my boost clock to 1170 and tdp slider at +145 and see 1242mhz boost clocks. If I drop it to 0 I will see lower clocks at max boost.

 

[RussianSensation]

Performance is nearly identical between them but there is one not-so-insignificant shortcoming of the 7950. The 2D frequency takes priority over the 3D frequency when there are tasks competing for the GPU resources. For example, if you watch a YouTube video while playing a game, the clock speed defaults to that of 2D frequency. The 670 doesn't exhibit this behavior and handles multitasking and task-switching more graciously than the HD 7950, which may be attributed to its new memory controller and dynamic voltage/frequencies. (Thank you, Cookie master for pointing it out and I now can also vouch for it)

It's an Adobe Flash video driver bug that's currently present on HD7900 series. I sent a report to AMD about it (and you can too if you want). The 7900 series drops clocks to 500mhz while watching Adobe Flash content (regardless if you are gaming or not at the same time), which is why your performance drops in half, if not more in the game. You can load almost any adobe flash video on the internet and experience this bug. You probably just haven't noticed it before since you weren't specifically gaming at that time or checking the GPU clock in MSI Afterburner. Sometimes the GPU is able to recover to the full overclocking speed and sometimes it's stuck at 500mhz until you close that browser tab even after the video has stopped playing. To fix this, all you have to do is right click on Youtube/Adobe Flash video and click Settings --> Uncheck Enable (GPU) Hardware Acceleration and the let your CPU accelerate YouTube videos. That's all it is. Thankfully, Adobe itself is already ditching flash for HTML5 on mobile and desktop can't come soon enough.

If for example you play a 1080P .MKV movie and game at the same time, this '500mhz GPU issue' is not present, which means it's not a multi-tasking issue for the GPU. On a more serious note, how do you game and watch a movie at the same time? You are gifted. :biggrin:

The native AO in NV drivers is a great feature.

 

[lopri]

Lopri, you cant measure VRAM that way. You need to use process explorer.

I heed your advice and checked out Processor Explorer (did not know that it could monitor GPU usages) and the numbers I see are pretty much the same as GPU-Z's.

GTX 670

HD 7950

It looks like what Processor Explorer calls "GPU System Memory" is what GPU-Z calls "Memory Usage (Dynamic)" for HD 7900 series. And for GTX 670 GPU-Z combine those two and report one value called "Memory Used."

In any case the "GPU System Memory" or "Memory Usage (Dynamic)" is pretty small. I have not seen it grow larger than 200 MB. It's usually below 100 MB.

 

[lopri]

@Russian Sensation: From my testing so far the fall-back on 2D frequency hasn't been limited to Flash. It has been the same for HTML5, or whenever DXVA is at work.

I can imagine a case where a clip is very demanding to the point it requires 3D frequency, though, but I haven't seen it with this generation of cards yet.

 

[lopri]

Lopri the slider for tdp on the gtx 670 wont affect clock speeds you can obtain via overclocking since you are raising the base clock too. What it does affect is the max boost clock you might see in your games under load. For example I set my boost clock to 1170 and tdp slider at +145 and see 1242mhz boost clocks. If I drop it to 0 I will see lower clocks at max boost.

I see. But the reviews I saw somehow left an impression that the TDP slider helps with overclocking (which, btw, is accomplished by frequency offsets) , so I thought that'd be the case.

 

[ShintaiDK]

It looks like what Processor Explorer calls "GPU System Memory" is what GPU-Z calls "Memory Usage (Dynamic)" for HD 7900 series. And for GTX 670 GPU-Z combine those two and report one value called "Memory Used."

In any case the "GPU System Memory" or "Memory Usage (Dynamic)" is pretty small. I have not seen it grow larger than 200 MB. It's usually below 100 MB.

There is only one that matters, GPU Dedicated. GPU-Z is pretty wrong with nVidia cards in terms of measuring VRAM usage by games.

For example:

As you can see.

 

[lopri]

You are artificially making a situation where the software readings may not match each other. It looks like you're running something that pushes the GPU usage to 100% and memory usage to the max as well. It's not surprising that a software is confused and/or not refreshing the readings at the same time another software does.

I suggest you load the GPU memory with something that doesn't stress the GPU core. Wait a few seconds till things settle and read the usage of memory.

I am not saying one software's reading is correct and the other is not. What I am saying is that the two software's readings are within the margin of error. (similar, that is)

 

[ShintaiDK]

No, you are making a situation that somewhat gets close to what you wish. Yet even your nVidia one is off by a margin of ~13.5%. Showing the usage for the process is the real deal, load or not.

With or without Areo. GPU-Z just cant get it right.

 

[f1sherman]

It's an Adobe Flash video driver bug that's currently present on HD7900 series. I sent a report to AMD about it (and you can too if you want). The 7900 series drops clocks to 500mhz while watching Adobe Flash content (regardless if you are gaming or not at the same time)

It's not a bug. It's how PowerPlay/UVD have been designed.
It has been like that since ages... HD3000 at least. Like I told you already

I am surprised though they carried this to HD7000.

 

[cmdrdredd]

I see. But the reviews I saw somehow left an impression that the TDP slider helps with overclocking (which, btw, is accomplished by frequency offsets) , so I thought that'd be the case.

Well, sorta does in a way. Like if you up the TDP your max boost clock will go up so in a way, you are getting a better overclock.

 

[RussianSensation]

It's not a bug. It's how PowerPlay/UVD have been designed.
It has been like that since ages... HD3000 at least. Like I told you already

I am surprised though they carried this to HD7000.

How come I never had this with my HD4890 or 6950 series then? I've used those cards extensively for almost 3 years. The 7970 is the first AMD card for me to have this issue on my system. Even before I sold my 6950 card, I was doing some testing with it using Cats 12.2 and 12.6. While mining and watching Youtube, the GPU clock would automatically go back up to 880mhz if I closed the web broswer/stopped watching the video. It doesn't do that on 7970 series. Sometimes it requires a restart to go back to 1150mhz clocks. So it's definitely not "since HD3000 series" issue. Also, disabling hardware acceleration for youtube fixes this completely with no side-effect since even Core 2 Duo 2.6ghz has been shown to play 1080P content without skipping frames.

 

[f1sherman]

Well that's what you proly had - video acc. turned off/not working

It's older than jesus seriously.
I still have nightmares about it from 4870 days, and my buddy with recently bought 6870 contacted me about it.

Here, for HD5000 from [H], from the list of bugs

Note:Will Not Be Fixed

Or from guru3d, workaround for HD6950 stuck at UVD clocks.

 

[RussianSensation]

Well that's what you proly had - video acc. turned off/not working

It's older than jesus seriously.
I still have nightmares about it from 4870 days, and my buddy with recently bought 6870 contacted me about it.

Here, for HD5000 from [H], from the list of bugs

Note:Will Not Be Fixed

From the thread you linked, Official fix: Buy an HD 6000 series card to replace your HD 5000 series card.

Like I said this is the first time I've encountered this bug in 3 years of using AMD cards. I know because I have been mining while often watching Flash video in YouTube for a while now. This problem didn't exist for me in 4890 and 6950 cards or I would have noticed it right away. This is pretty much the first thing I noticed when I got the 7970 because my old AMD cards never exhibited this behaviour. Also, it was only after I got the 7970 that I googled the "Disable hardware acceleration" fix since on my 4890/6950 cards the GPU would boost back up to 3D clocks when I would close the browser tab and the 7970 didn't.

I can't comment on DivX + gaming at the same time because I use Media Player Classic/K-Lite Codec Pack for all my 1080P movie desktop content. There is even the Mega Codec pack with even more features.

So I mean, really both of those "multi-tasking" issues are addressable with software fixes:

1) turn off hardware acceleration for Adobe Flash and let CPU take over
2) Replace DivX with a different (and imo superior) player in the first place that plays just about anything.

 

[lopri]

It's not a bug. It's how PowerPlay/UVD have been designed.
It has been like that since ages... HD3000 at least. Like I told you already

I am surprised though they carried this to HD7000.

I don't believe that is correct. For example, my HD 6870 would idle at 300/300, and when DXVA is utilized it would either clock to 300/1050 or 500/1050 depending on the load. Once a 3D application is launched, it would ratchet up the clock to 915/1050 regardless of whether DXVA is at work in the background.

 

[blackened23]

Shintaidk, please tell me your computer doesn't use that color theme !

 

[ShintaiDK]

Shintaidk, please tell me your computer doesn't use that color theme !

It does :biggrin:

 

[Joseph F]

It does :biggrin:

D: