How to Safely Overclock an AMD Radeon HD 6670 for Better Performance

At the time of its appearance on the market, the AMD Radeon HD 6670 video card was a typical representative of the middle segment, occupying the niche of cheap, but at the same time sufficiently productive solutions for its price. Its main competitors were the GT 440 and GTS 450 cards from NVidia.

At the same time, despite the fact that the declared potential of the AMD novelty was significantly higher than that of its competitors, this could not be said in terms of the adapter’s performance. The reason was the type of RAM used for the card – the outdated DDR3 (besides, operating in asynchronous mode with a video chip) could not fully realize all the card’s capabilities.

With the release of the latest revision of the card with modern GDDDR5 memory, the situation was corrected the Radeon HD 6670 was able to bypass both the GT440 and the GTS450.

Many critics received hostility to such a move by AMD, since the use of modern memory microcircuits significantly increased the cost of this card, although it did not take it out of the middle segment (either in terms of price or performance).

Nevertheless, in terms of the aggregate characteristics, this solution was much more attractive than the GTS 450 released six months ago and had almost 1.5 times less consumption.

How T Overclock AMD Radeon HD 6670

General characteristics of the radeon 6670 video card

The HD 6700 card has the following characteristics:

  • GPU: AMD Turks XT;
  • used adapter architecture: TeraScale 2nd version;
  • technical process 40 nm;
  • interface: PCI Express 2.1 x16;
  • used memory: DDR3, later GDDR5;
  • form factor: slim, later low-profile;
  • power consumption: idle – 11 W, at maximum load – 66 W;
  • connectors: DVI, Display Port, D-SUB.

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The main characteristic of the video adapter, which to a large extent determines its performance, is the performance when working with 32-bit single-precision numbers (single-precision floating-point format).

It is denoted by the FP32 index and is measured in the number of such operations that the GPU can perform per second at the nominal frequency. It is measured in flops, the name comes from the English “floating-point operation per second”.

The performance of the Radeon HD-6670 for 32-bit numbers is 768 gigaflops or 768 billion operations per second. This is the most important characteristic that the user should be interested in.

All other characteristics, although they carry some amount of important information, their interest for the user is very dubious. Rather, they are important to engineers and designers involved in the development of personal computer components.

These characteristics include:

  • scene fill rate in pixels: 6.4 GPix / s;
  • scene filling speed in texels: 19.2 GTex / sec;
  • memory bus bandwidth for DDR3: 25.6 Gb / s;
  • memory bus bandwidth for GDDR5: 64 Gb / s.


The graphics processor used in this video controller was marked Turks XT and was a traditional solution based on the Tera Sacle architecture of the second version. In its configuration, it completely repeated the Turks Pro used in the earlier HD65xx cards. The only difference was in the higher frequency at which the GPU worked and in the higher heat dissipation (800 MHz verses 650 and 66 W versus 44, respectively).

The dimensions of the chip were 118 square meters. mm; it housed 716 million transistors.

The processor has the following kernel configuration:

  1. number of unified shader processors – 480;
  2. number of texture units 24;
  3. the number of rasterization blocks is 8.

Shader processors are organized according to the scheme 6: 16: 5 – 6 SIMD-blocks of 16 GPGPU in each with a breakdown into 5 ALUs (6 x 16 x 5 = 480).

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Video RAM

The video adapter chip (Turks XT) works with 128-bit RAM. Inside the chip, there are two 64-bit controllers operating in Dual Channel mode, which is an acceptable solution for a card in the budget segment.

The 6670 accelerators were produced in two versions: using DDR3 and GDDR5 memory. Moreover, both types of memory did not correspond to it a little. DDR3, clocked at 667 MHz, was slower than the chip, while GDDR5, clocked at 1000 MHz, was slightly faster.

In later models, it was possible to achieve synchronous operation of the memory and the chip at a frequency of 800 MHz.

The card could not fully reveal the potential of GDDR5 memory, although some of its models were equipped with high-speed memory from Hynix with an operating frequency of 1250 MHz. 

As a result, the memory chips had to run at a reduced frequency. The full potential of GDDR5 was realized in the next model of the series the 6770 cards.

The memory capacity of the adapter, depending on the manufacturer and batch, can be 512, 1024, and 2048 MB.

Standards and technology support

The HD6670 card, based on the Terfscale-2 microarchitecture, supports all technologies specific to it. There were no restrictions or cuts in any functions in the entire 66xx series.

APIs used:

  • DirectX 11_0;
  • OpenGl – 4.4;
  • OpenCl – 1.2;
  • Shader – 5.0.

Naturally, the card incorporates all AMD’s proprietary features: AMD Eyefinity, MAA, and others.

The card used the UDV 2.2 ASIC video decoder. Energy-saving technology – dynamic PowerPlay, the presentation of which took place in this microarchitecture.

The HD6670-based video system can support 2 to 6 monitors with 4K resolution (2560 x 1600 pixels).

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Support for HAS and API Vulcan was not provided in all generations of Terascale.

How T Overclock AMD Radeon HD 6670?

How T Overclock AMD Radeon HD 6670?

Overclocking Test and Result

The direct competitor of this card is GeForce GTS 450 from NVidia. It has about the same performance, but its power consumption is slightly higher (106 W instead of 66 W for an AMD representative).

Important! The FP32 performance of the HD6670 is 768 GFlops, and the GTS 450 is 602 GFlops. Taking into account that the speed of AMD stream processors is about 20% lower, the real performance in 3D applications of the cards will be about the same.

This is fully confirmed by the test results. In synthetic (3DMark Vantage and 3DMark 11), the cards work at about the same speed: in the Xtreme test, HD6670 leads with an advantage of 9%, but in Entry, it lags behind by about the same percentage. Performance test results differ by no more than 5% in favor of AMD products.

In gaming tests, cards with DDR3 memory are about 15-20% behind cards using GDDR5, which roughly corresponds to the performance of the GT 440 from NVidia.

If we compare HD-6670 with GDDR5 memory and GTS450, the latter works faster in applications not optimized for AMD Direct3D (Far Cry 2, Call of Juarez). Sometimes its advantage reaches 30%; at the same time, as noted earlier, the “synthetic” performance of video cards is the same.

However, in programs with code optimization taking into account the technological innovations of AMD (for example, AVP, Metro 2033, and the like), the performance of the adapters is identical.

The Terascale-2 architecture inherited from the 5000 series was not very good in overclocking. This was fixed a year later, with the appearance of its third version and the release of 69xx maps.

However, with the transition to the new architecture, the 6300-6800 series was not re-released, although in fact the first 6900 chips were produced two months earlier than the same 6600 series.

What caused AMD to release an obviously older version of the chips later than a newer one remains a mystery. Nevertheless, this happened, and the budget segment turned out to be filled with, albeit not bad, but outdated video cards, the overclocking of which left much to be desired.

The Sapphire Radeon HD 6670 1GB video cards proved to be the most effective in overclocking. They were overclocked up to 883 MHz in chip frequency and up to 1143 MHz in video memory frequency (which corresponded to overclocking + 10% and + 14%). These figures were rather mediocre since the real gain in video adapters’ performance in games and synthetic tests were about + 10.5%.

Hi, fellow tech enthusiasts! I’m Syed Kashif Shah, and I’m proud to be your go-to expert for all things like problems, suggestions, recommendations related to graphics cards. As a seasoned Technology Consultant and Hardware Enthusiast, I’ve spent years in the graphics card troubleshooting and repair field.