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Zotac GeForce GTX 950 Video Card

Zotac GeForce GTX 950 Video Card

December 1, 2015 by Lawrence Lee

Product
Zotac GeForce GTX 950 (ZT-90601-10L)

Graphics Card
Manufacturer
Zotac
Street Price
US$150

Since their release last year, Nvidia's second generation Maxwell GPUs have been heavily favored by enthusiasts looking to build quiet high performance gaming PCs. The GTX 900 series is wonderfully energy efficient, consuming significantly less power than their AMD counterparts. The graphics card is usually the most power hungry component in any serious gaming machine, so this savings results in a drastic reduction in waste heat, making it easier to cool quietly. This is especially important in smaller form factors which have inherently less ventilation and fewer fans.

GTX 900 Series Comparison
Model
GTX 980
GTX 970
GTX 960
GTX 950
Transistor Count
5.2 billion
5.2 billion
2.9 billion
2.9 billion
ROPs
64
56
32
32
CUDA Cores
2048
1664
1024
768
Core Freq.
1126 MHz
1050 MHz
1127 MHz
1024 MHz
Boost Freq. (max)
1216 MHz
1178 MHz
1178 MHz
1188 MHz
Memory Freq.
7010 MHz
7010 MHz
7010 MHz
6610 MHz
Memory Size
4GB
3.5+0.5GB
4GB/2GB
4GB/2GB
Memory Bus
256-bit
224+28-bit
128-bit
128-bit
TDP
165W
145W
120W
90W
Starting Price
US$490
US$310
US$210/$185
TBD/US$150

Until now, the GTX 900 series has priced out the higher end of the market, with the ~US$200 GTX 960 as the bottom rung on the ladder. The newly released GTX 950 expands down to the US$150 level, giving price-sensitive users a taste of what more fortunate gamers have been enjoying. It's essentially a cut-down GTX 960 with 3/4 the number of CUDA cores and slightly lower clock and memory speeds. With this downgrade in horsepower comes a sizable 30W TDP drop. Currently it's only available with 2GB of video memory but 4GB models are on the way, though it's questionable whether the extra RAM is useful on a card of this caliber.



Zotac GeForce GTX 950 packaging.



The card.

Our first sample is the plainly named Zotac GeForce GTX 950, their most basic model with just a single fan. Zotac has two other 950s equipped with dual fan heatsinks, but this one is preferable for extremely small gaming PCs. While it occupies dual slots, it's quite short, about the same length as a mini-ITX motherboard. Clock speeds aren't as high as most models, but it's still factory overclocked like most cards these days. More importantly, it can fit in spaces larger models cannot. The question is whether the cooler is up to the task, as a bum heatsink/fan could negate all the good things going for it.

Specifications: Zotac GTX 950 (ZT-90601-10L)

(from the
product web page
)
GPU GeForce GTX 950
CUDA Cores 768
Video Memory 2GB GDDR5
Memory Bus 128-bit
Engine Clock Base: 1089 MHz

Boost: 1266 MHz
Memory Clock 6610 MHz
PCI Express 3
Display Outputs DisplayPort 1.2: 4K @ 60Hz

HDMI 2.0: 4K @60 Hz

2 x DL-DVI: 2560x1600
HDCP Support Yes
Multi Display Capability Quad Display
Recommended Power Supply 300W
Power Consumption 90W
Power Input 6-pin
DirectX 12 API feature level 12_1
OpenGL 4.5
Cooling 90mm single fan
Slot Size Dual Slot
SLI 2-way
Supported OS Windows 10 / 8 / 7 / Vista / XP
Card Length 208 mm x 111.15 mm
Accessories N/A

PHYSICAL DETAILS

The Zotac model is of standard width and measures just 17.3 cm or 6.8 inches, about the same span as a mini-ITX motherboard. The small size and mere 90W TDP makes it an excellent option for a compact gaming PCs housed in a small/shallow case. The card weighs 440 grams (just under 1 lb) with the cooler accounting for 260 grams of the total.



The card is covered with a simple plastic shroud and is cooled by a radial style heatsink with a single 92 mm fan.



Outputs: DVI-D, DVI-I, HDMI, and DisplayPort.



With its low TDP, the GTX 950 requires just one 6-pin PCI-E power cable.



Removing the cooler is a simple matter of loosening four spring-loaded screws around the GPU core. There are two additional screws holding down a dedicated VRM heatsink.



The heatsink is fairly small, not even extending to the far side of the shroud. Contact between the aluminum base and the GPU core is facilitated by a thin layer of thermal compound. The die is exposed but surrounded by a shim, and rubber pads have been placed on the outside as an additional precaution.

TEST METHODOLOGY

Test Platform

  • Intel Core i3-2100 processor, Sandy Bridge core, dual core 3.1 GHz, integrated HD 2000 graphics, TDP of 65W
  • Scythe Kotetsu CPU cooler - Scythe
    Slip Stream
    500RPM 120mm fan
  • MSI Z77A-G43 motherboard, Z77 chipset, ATX
  • Kingston HyperX Genesis memory, 2x4GB, DDR3-1600
  • Kingston HyperX 3K solid state drive - 120GB, 2.5-inch, SATA 6 Gbps
  • Kingwin Lazer Platinum
    power supply, ATX v2.2, 80 Plus Platinum, 1000W total output, 83A on +12V rail
  • Fractal Design Define R5 case - ATX, stock 140mm fans
  • Microsoft
    Windows 7 Ultimate
    operating system - 64-bit



Our GPU test system.

Measurement and Analysis Tools

Testing Procedures

Our test procedures are designed to determine the power consumption, noise, and heat produced by the card/cooler with the system in various states. In addition to testing under "normal" conditions, we also perform a torture test consisting of FurMark running in conjunction with Prime95 to stress both the graphics card and processor simultaneously. This combination is more demanding on the CPU and GPU than any real gaming session. This final result is not indicative of a real-world situation, but rather a worse-case scenario; If it can cool the card and its components adequately it means there will be some degree of thermal headroom when deployed in a more conventional situation.

By adequately cooled, we mean cooled well enough that no misbehavior
related to thermal overload is exhibited. Thermal misbehavior in a graphics
card can show up in a variety of ways, including:

  • Sudden system shutdown, reboot without warning, or loss of display signal
  • Jaggies and other visual artifacts on the screen.
  • Motion slowing and/or screen freezing.

Any of these misbehaviors are annoying at best and dangerous at worst —
dangerous to the health and lifespan of the graphics card, and sometimes to
the system OS.

Aftermarket coolers are installed on an ASUS GeForce GTX 680 DirectCU II OC, a factory-overclocked single GPU card that draws 226W by our estimates. The stock VRM heatsink is left on if possible. The cooler's fan(s) is connected to the motherboard (if possible) and its speed is changed to various levels to represent a good cross-section of its airflow and noise performance.

Ambient Noise Level

For noise measurements, our mic is positioned at a distance of one meter from the center of the case's left side panel at a 45 degree angle.

Our test system's CPU fan is a low speed Scythe that is set to full speed at all times while the two Fractal 140 mm case fans are connected to case's integrated fan controller. Three standard speed settings have been established for testing.

GPU Test System:

Anechoic chamber measurements
Case Fan Setting
High
24 dBA
Med
15 dBA
Low
12~13 dBA

When testing video cards and coolers with active cooling, the low setting will be used. For passive cards and heatsinks, all three settings will be tested to determine the effect of system airflow on cooling performance.

Estimating DC Power

The following power efficiency figures were obtained for the
Kingwin LZP-1000
used in our test system:

Kingwin LZP-1000 Test Results
DC Output (W)
22.2
41.9
65.5
90.7
149.0
199.6
251.2
300.3
400.9
AC Input (W)
35
56
81
105
166
211
265
322
426

This data is enough to give us a very good estimate of DC demand in our
test system. We extrapolate the DC power output from the measured AC power
input based on this data. We won't go through the math; it's easy enough
to figure out for yourself if you really want to.

TEST RESULTS

System Measurements: GPU Test System with Zotac GTX 950
State
Idle
Prime95
Resident Evil 6 (Peak)
Prime95 + FurMark
GPU Fan Speed
Off
1670 RPM (56%)
1270 RPM (33%/min)*
1740 RPM (58%)
1270 RPM (33%/min)*
CPU Temp
21°C
40°C
41°C
42°C
50°C
52°C
MB Temp
30°C
31°C
35°C
37°C
36°C
38°C
GPU Temp
35°C
36°C
64°C
70°C
64°C
69°C
GPU Core Clock
135 MHz
1304 MHz
949 MHz
937 MHz
System Power (AC)
36W
76W
150W
151W
164W
12~13 dBA
19 dBA
14 dBA
20 dBA
14 dBA
*fan speed adjusted manually to hit 80°C target

CPU fan at 500 RPM, system fans at 580 RPM.

Ambient noise level: 10~11 dBA

System noise level (on int. graphics): 12~13 dBA

Ambient temperature: 21°C

Unlike most lower-end video cards, the Zotac GTX 950's fan shuts off when the GPU is running cool, making it completely silent when the card is not being heavily taxed. Our test system's CPU fan and system fans run at very low speeds, so the machine generates just 12~13 [email protected] at idle and with Prime95 stressing the CPU.

Our Resident Evil 6 benchmark puts a greater combined load on the system, doubling the system power draw to 150W AC. The GPU fans spin up here, peaking at 1670 RPM (56%), bringing the total noise level up to 19 [email protected] The stock fan control system is aggressive, attempting to keep the core temperature at/around 64°C. Manually setting the fan speed to minimum (1270 RPM, 33%) results in the GPU heating up by 6°C and a sizable 5 dB noise reduction.

Prime95 + FurMark, a full synthetic torture test, is only moderately more demanding due to some premature throttling. The GPU core clock drops by 27~28% compared to the Resident Evil 6 test even though fan runs fast enough to deliver similar temperatures.

The Zotac GTX 950 fan is not great acoustically, especially compared to the other fans in our test system, but it's off when the GPU is not being stressed, and even when it is active, it doesn't have to work particularly hard. At the minimum speed of 1270 RPM, there is some audible clicking if you put your ear right next to the side panel but it's virtually inaudible at about half a meter and beyond.

At 1740 RPM, the speed it reached during our FurMark torture test, the fan generates a moderate pitched hum that isn't too unpleasant. The pitch rises and becomes more grating with speed but it's unlikely to ever run that fast under normal conditions. You can always slow it down manually to your liking. Our sample also emits some faint coil whine during the Resident Evil 6 test but it can only be heard from the back of the case or if the side panel is removed.

Comparison: GPU Test System, Resident Evil 6 (Peak, 80°C Target Temp)
GPU Model
CPU Temp
GPU Temp
Clock Speed
GPU Fan Speed
SPL @1m
System Power (AC)
Zotac GTX 640 Zone (fanless)
33°C
80°C
902 MHz
N/A
12~13 dBA
82W
Zotac GTX 750 Zone (fanless)
36°C
79°C
1037 MHz
N/A
12~13 dBA
110W
Zotac GTX 950
42°C
70°C
1304 MHz
1270 RPM (minimum)
14 dBA
151W
Asus HD 6850 DirectCU
41°C
80°C
790 MHz
1750 RPM
17 dBA
166W
Asus HD 7870 DirectCU II
46°C
80°C
1100 MHz
1290 RPM
13~14 dBA
208W
Zotac GTX 970 Extreme Core
46°C
72°C
1418 MHz
1090 RPM (minimum)
14 dBA
215W
CPU fan at 500 RPM, system fans at 580 RPM.

Ambient noise level: 10~11 dBA

System noise level (on int. graphics): 12~13 dBA

Ambient temperature: 21°C

As video cards are equipped with fan control systems of varying aggressiveness, comparing physical characteristics is unfair without controlling for a single factor. The comparison table above has taken this into consideration, using results obtained by manipulating the fans to achieve the same 80°C GPU temperature (at 21°C ambient) during our Resident Evil 6 test.

Under these conditions, the Zotac GTX 950 is fairly quiet compared to previous low-mid range cards we've tested, only being decisively beaten by fanless models with lower power requirements. Also note that it accomplishes this with a GPU temperature of only 70°C as its minimum fan speed is too high to allow for any higher GPU temperature.

Comparison: GPU Test System, Prime95 + FurMark (80°C Target Temp)
GPU Model
CPU Temp
GPU Temp
Clock Speed (% vs. RE6)*
GPU Fan Speed
SPL @1m
System Power (AC)
Zotac GTX 640 Zone (fanless)
43°C
97°C
902 MHz (100%)
N/A
12~12 dBA
117W
Zotac GTX 750 Zone (fanless)
44°C
90°C
1032 MHz (99.5%)
N/A
12~13 dBA
137W
Zotac GTX 950
52°C
69°C
937 MHz (71.9%)
1270 RPM (minimum)
14 dBA
164W
Asus HD 6850 DirectCU
53°C
80°C
790 MHz (100%)
2460 RPM
22~23 dBA
202W
Zotac GTX 970 Extreme Core
57°C
74°C
1001 MHz (70.6%)
1090 RPM (minimum)
14 dBA
228W
Asus HD 7870 DirectCU II
56°C
80°C
1100 MHz (100%)
1770 RPM
16~17 dBA
247W
*Percentage of clock speed compared to Resident Evil 6 test (peak, auto fan control).

CPU fan at 500 RPM, system fans at 580 RPM.

Ambient noise level: 10~11 dBA

System noise level (on int. graphics): 12~13 dBA

Ambient temperature: 21°C

Comparing Prime95 + FurMark using the same parameters yields different results and comes with complications due to the way modern GPUs adjust their clock speed in response to temperature at stock settings. However, the difference in clock speeds between this test and the Resident Evil 6 test is shown, so you can see exactly how much each card slows down.

The GTX 950 and GTX 970 suffer from the same issue during this test, with both cards clocking down by almost 30%, allowing them stay well under the target temperature despite running at their respective minimum fan speeds.

Energy Efficiency Comparison (Default Fan Control)

Under light load, the Zotac GTX 950 is quite thrifty with power, using about same wattage as a fanless Zotac GTX 750, and slightly less than the Asus GTX 960 Strix.

Power consumption under heavy load is quite modest with the system drawing 150W in our gaming tests, noticeably less than the GTX 960.

Converting the AC system power draw to DC and comparing the figures to those we obtained running on integrated graphics allows us to estimate the absolute power consumption of the graphics cards we've tested over the past few years, regardless of the changes in our GPU test system over time. The GTX 950 comes in at 11W idle and 97W on full theoretical load.

SOFTWARE

The card ships with Zotac's unattractive FireStorm utility. The UI appears somewhat dated by modern standards. The main screen displays the GPU core temperature prominently on a dial with a chart tracking the core and memory frequencies on the left, and overclocking functions on the right. Three overclocking presets (2D, 3D, 3D+) are offered if you choose to use the "Quick Boost" feature while "Advance" will bring up manual control. The "Gamer" button does not seem to do anything at all.

The manual settings are similar to those offered by competing video card makers. The app allows the GPU core and memory to be increased by 1000 MHz and 3305 MHz respectively, the voltage can receive a 100 mV bump, and the power target can be pushed to 120% of stock.

The manual fan control settings is rather disappointing. The fan speed graph resembles a series of steps as it only allows plot points to be positioned in 10%/10°C intervals so it's hard to fine-tune.

A supplementary monitoring panel can be pulled up on the left side but you can't choose what it tracks. The scale of the graphs is tiny as well, as the interface is crammed into a small space.

MP3 SOUND Recordings

These recordings were made with a high resolution, lab quality, digital recording
system inside SPCR's own 11 dBA ambient anechoic chamber, then converted to
LAME 128kbps encoded MP3s. We've listened long and hard to ensure there is no
audible degradation from the original WAV files to these MP3s. They represent
a quick snapshot of what we heard during the review.

Each recording starts with ambient noise, then 5~10 second segments of product
at various states. For the most realistic results,
set the volume so that the starting ambient level is just barely audible, then
don't change the volume setting again while comparing all the sound files.

FINAL THOUGHTS

The Zotac GTX 950 manages to operate silently or at fairly quiet levels despite having an unimpressive cooling solution. This is a testament to Nvidia's energy efficient GTX 900 series, the 950 being the latest and most frugal model thus far. A modest aluminum heatsink with a single 92 mm fan is more than sufficient for handling its thermal demands, and while the fan control is overly enthusiastic, it is easily calmed with software. The included FireStorm utility leaves much to be desired in both looks and functionality — the Asus GPU Tweak and the MSI Afterburner applications are more polished GPU tweakers. Our sample also emits a touch of coil whine but it's difficult to hear, and while the fan's sound quality is just average, it is never pushed hard enough to become an issue.

Consensus among other review sites peg the GTX 950's performance level as similar to that of the AMD R9 270X but 15~20% slower than the GTX 960, though given the small price difference between the two cards, they both offer similarly good value. The Zotac GTX 950 is capable of providing a smooth gaming experience at 1080p resolution with medium to high image quality settings. This Zotac isn't as highly clocked as competing models but at US$150, the most affordable, and its short length should appeal especially to SFF PC enthusiasts. It's a solid budget bang-for-your-buck graphics card no matter what case you use, and also close to ideal if you're looking to downsize.

Our thanks to Zotac for the GeForce GTX 950 video card sample.



The Zotac GeForce GTX 950 is recommended by SPCR

* * *

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Asus GeForce GTX 960 Strix OC Edition

* * *

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