Diamond Stealth VRAM
The Stealth VRAM was an enhancement on the earlier Stealth from 1991 with 1 MB of fast VRAM as standard, accessible via a 32-bit wide memory bus. It also got the Sierra HiColor DAC as standard which was a cost option on the earlier Stealth.
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Released | March 1992 |
| Bus | ISA 16-bit | |
| Chipset | S3 86C911 (or S3 86C924 later on) | |
| Standards | Hercules, CGA, EGA, VGA | |
| Memory | 1 MB VRAM | |
| Ports | 15-pin DSUB (video out) 26-pin VGA Feature connector |
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| RAMDAC | Sierra SC11483CV (HiColor) or Diamond SS2410 (True Color) | |
| Part # | 38-000126 | |
| FCC ID | FTUSTARV1 | |
| Price | At launch: $445 | |
| See Also | Diamond Stealth, Diamond Stealth 24 |
The S3 86C911, codenamed Carrera, was the first graphics chip produced by the company. The first cards that used it arrived in late 1991, including the Orchid Fahrenheit 1280. This was shortly followed by a number of other manufacturers jumping on the bandwagon, releasing their own cards centered around this same graphics accelerator chip.
The 1 MB of video memory allowed the card to display at resolutions up to 1,280 by 1,024 using custom drivers for applications such as AutoCAD, though there was no Windows driver mode that provided this resolution. The highest Windows resolution available was 1,280 x 960 in 16 colours.
Supported graphics modes are:
| Resolution | Colours | Refresh Rate |
|---|---|---|
| 640 x 480 | 32,768 or 65,536* | 72 Hz |
| 800 x 600 | 256 | 72 Hz |
| 1024 x 768 | 256 | 72 Hz |
| 1280 x 960 | 16 | 45 Hz (i) |
| 1280 x 1024 | 16 | 45 Hz (i) |
* 32,768 colours if a 15-bit RAMDAC is installed, 65,536 if 16-bit. Most Stealth VRAMs are the original type with the 86C911 chip and a 15-bit RAMDAC, so are limited to 32,768 colours.
The card natively supported VESA VBE 1.0 extensions in the BIOS, so you would need to run UNIVBE or similar to get it up to VESA VBE 3.0 standard (if required).
The Diamond Stealth VRAM was succeeded in 1993 with the launch of the Diamond Stealth 24 and Stealth 24VL, which used the latest S3 graphics accelerators that year which were the 86C801 and 86C805 respectively.
Board Revisions
Several revisions of the Diamond Stealth VRAM exist, including B2 and C4. Rev B2 uses ZIP memory packages (as seen in the picture at the top) while C4 uses SOJ memory packages.
Some late Stealth VRAM cards came with the later S3 86C924 graphics accelerator, which was fully backward-compatible with the 86C911 but added support for 24-bit True Color. Some of these later cards were fitted with the Diamond SS2410 True Color RAMDAC which supports 24-bit colour depths and used v2.33 of the BIOS ROM, though others still came with the Sierra SC11483 15-bit (Hi Color) RAMDAC and used a v2.32 ROM.
The BIOS is split across two Texas Instruments TMS2C256-150 (or compatible) 28-pin DIP ICs, seemingly designed with the low bytes in the leftmost chip and high bytes in the rightmost chip, though dumping the code reveals both are identical.
Any BIOS version up to and including to v2.32 can be used on both board revisions - I have never seen BIOS v2.33 on a card with a 911 (only on later 924-based Stealth VRAM cards), so it might be incompatible or maybe just doesn't add any value since the 911 was limited to 15- and 16-bit colour depths.
So in summary, there appear to be the following flavours of Diamond Stealth VRAM:
- 86C911 chip, Sierra SC11438 15-bit RAMDAC (32,768 maximum colours), ZIP or SOJ memory, BIOS ROM v2.30 - v2.32
- 86C911 chip, Diamond SS2410 16-bit RAMDAC (65,536 maximum colours), ZIP or SOJ memory, BIOS ROM v.230 - v2.32
- 86C924 chip, Sierra SC11438 15-bit RAMDAC (32,768 maximum colours), ZIP or SOJ memory, BIOS ROM v2.32
- 86C924 chip, Diamond SS2410 16-bit RAMDAC (65,536 maximum colours), ZIP or SOJ memory, BIOS ROM v2.33
Competition
In 1992, Windows 3.1 graphics acceleration was becoming more important due to the rapid rise in popularity of Windows applications. Non-accelerated 'dumb frame buffer' graphics cards were fine for the standard VGA resolution of 640 x 480, but above 800 x 600 or when using higher colour depths that were popularised by an increase in monitor sizes, Windows could be sluggish or have to be run in a lower refresh rate.
In 1992 'local bus' graphics solutions were incredibly rare, with only Chips & Technologies having already worked on a Local Bus architecture for their graphics offerings with the Wingine. As such, the ISA bus was still the bottleneck to vastly improving graphics data throughput. The intermediate solution most graphics card manufacturers chose was to use faster video memory along with a faster on-card bus between the graphics accelerator chip and the onboard video memory to eek out the best performance possible while still running on the ISA bus.
The Diamond Stealth VRAM went head-to-head with the ATI Graphics Ultra, Number Nine GXi, STB Wind/X Ultra, Orchid Fahrenheit 1280, Actix Graphics Engine, and Genoa WindowsVGA. The STB, Orchid, Actix and Genoa cards also shared the same 86C911 chipset, so performance was virtually the same between these - only driver optimisations would make a slight difference, so manufacturers differentiated themselves mostly on price (though the STB card also came bundled with a Logitech bus mouse).
The ATI Graphics Ultra with its Mach8 accelerator shared a similar 1 MB of VRAM but was slightly higher-performing than the S3 911. It was also more capable with a top resolution of 1280 x 1024 at an excellent flicker-free 87 Hz interlaced refresh rate and 1024 x 768 at 76 Hz non-interlaced.
The STB Wind/X Ultra was at the top of the S3 performance pile, able to display 1280 x 1024 at an 88 Hz interlaced refresh rate while many others could only manage the same resolution at between 43.5 and 48 Hz. The STB was about the same price as the Stealth VRAM, at $439 list. All the cards were capable of 1024 x 768 in at least 70 Hz non-interlaced. The Genoa card was at the budget end of the scale at $319 though if all you cared about was 1024 x 768 and lower resolutions, it was a great buy, offering similar performance to the rest.
In 1992, competing graphics accelerators arrived, including the Western Digital 90C31, IIT AGX, ATI Mach32, and Headland HT216.
In the Media
Although the board is too new to have established a street price, figure about $299 for the current standard configuration.
The Stealth [VRAM] is based on S3's 86C911 accelerator, but Diamond claims to have improved the chip's performance by enhancing the S3 drivers. In fact, it earned top honors on PC Magazine Labs' 16-color Windows tests and commended itself quite favorably when upped to 256 hues on the Windows tests. It was second only to the higher-priced ATI Graphics Ultra on the 256-color Windows tests. On our VGA tests, it shared best-of-the-S3-class scores with Portacom.
The board is amazingly compact, just about 6.75 inches long and XT-height. Most of the circuitry is surface-mounted and a VESA-style feature connector (a header) allows future enhancements.
The Stealth supports a 72-Hz refresh at 800-by-600-pixel resolution and either 60 Hz or 70 Hz at 1,024 by 768. Unfortunately, interlacing is required at its top, non-Windows 1,280-by-1,024 resolution level - at a horizontal frequency of 48.9 KHz. Including 1MB in the standard configuration was a good move, as it is required (as with other boards) for 256-color operation beyond VGA, for 16 colors at 1,280 by 1,024 or if you want use of the Sierra RAMDAC.
Diamond wrote VESA program calls into its proprietary (rewritten S3) BIOS and claims 100 percent VBE compatibility in its BIOS. We were unable to detect this on our tests, however. On the other hand, the Diamond-supplied Windows and display-list AutoCAD drivers worked flawlessly.
The Stealth is easy to get going, having only two jumpers for setup; one that was used for VRAM size selection - no longer necessary since the move to 1MB as standard equipment - and another for enabling/disabling the 16-bit BIOS. A four-switch DIP bank for matching monitor type for best refresh rate and enabling speed-enhancing features such as fast BIOS support is also present. The switches are accessible through the board's rear panel after installation and are well documented in the Stealth manual." PC Magazine, March 1992
While the scores were relatively close, we did find differences among the products.
The top performer, STB Wind/X Ultra was a fine all-round product. It was the quickest board on our high end platform is solidly built, and is backed by STB's superb support policies. The STB is the only board that ships with a bus mouse port.
The Diamond Stealth VRAM tied with Orchid [Fahrenheit 1280] for the second spot. It offers the most extensive driver support, with drivers available for OS/2. The speed scores were quick, the board is well designed, and Diamond offers impressive support policies to complement its product. " InfoWorld, May 1992
Performance
I ran some basic DOS performance tests on this card on a much later motherboard running a Pentium III-750 (to avoid other components being a bottleneck for the card's tests). Here's a side-by-side comparison of the results of the Diamond Stealth VRAM, an ATI VGA Wonder GT (basically an ATI Graphics Ultra), a Tseng Labs ET4000AX card, and a Trident TVGA-8900CL with 70ns DRAMs:
| Diamond Stealth VRAM 80ns (1992) | ATI VGA Wonder GT 100ns (1993) | Tseng Labs ET4000 1 MB 80ns (1992) | Trident 8900CL 1MB 70ns (1992) | |
|---|---|---|---|---|
| Doom timedemo | 25.6 fps | 34.3 fps | 37.2 fps | 44.5 fps |
| Superscape VGA Benchmark 1.0 | 32.2 | 71.4 | 71.4 | 90.9 |
| Superscape VGA Benchmark 1.0c | 31.9 | 67.7 | 69.3 | 83.6 |
| Chris' 3D Bench | 34.2 (20.5 fps) | 89.0 (53.4 fps) | 92.5 (55.5 fps) | 117.5 (70.5 fps) |
| Chris' 3D Bench SVGA | 7.5 (4.5 fps) | (VESA not found)* | 23.1 (13.9 fps) | 27.9 (16.7 fps)** |
| PC Player 320x200 x 8 bpp | 22.7 | 53.0 | 54.8 | 66.5 |
| PC Player 640x480 x 8 bpp | 3.7** | (VESA not found)* | (VESA not found)* | 15.7 |
| Vidspeed | 65,024 bytes/ms normal RAM 3121 - 3324 (text) 1602 - 1756 (CGA) 1601 - 1757 (EGA) 1592 - 1602 (VGA) 1322 - 1322 (SVGA) |
65,024 bytes/ms normal RAM 3543 - 3555 (text) 2613 - 3527 (CGA) 2608 - 2619 (EGA) 2614 - 3509 (VGA) 1730 - 3593 (SVGA) |
65,024 bytes/ms normal RAM 4561 - 4571 (text) 4545 - 4555 (CGA) 3580 - 3580 (EGA) 3579 - 3605 (VGA) 3579 - 3605 (SVGA) |
65,024 bytes/ms normal RAM 4394 - 4413 (text) 4199 - 4391 (CGA) 4201 - 4320 (EGA) 4082 - 4388 (VGA) 4082 - 4389 (SVGA) |
| Dr.Hard Video Performance | 786,239 cps (direct text 8-bit) 1,550,639 cps (direct text 16-bit) 263,972 cps (write via BIOS) 18,199 cps (write via DOS) 146,247 pixels/s (write via BIOS) 1.55 MB/s text 8-bit 3.09 MB/s text 16-bit 3.15 MB/s text 32-bit 1.57 MB/s graphics 8-bit 1.65 MB/s graphics 16-bit 1.65 MB/s graphics 32-bit 3.1 MB/s max video transfer rate |
920,919 cps (direct text 8-bit) 1,761,759 cps (direct text 16-bit) 358,903 cps (write via BIOS) 18,199 cps (write via DOS) 260,399 pixels/s (write via BIOS) 1.81 MB/s text 8-bit 3.55 MB/s text 16-bit 4.38 MB/s text 32-bit 1.80 MB/s graphics 8-bit 3.51 MB/s graphics 16-bit 4.30 MB/s graphics 32-bit 4.3 MB/s max video transfer rate |
22,578,919 cps (direct text 8-bit) 46,905,039 cps (direct text 16-bit) 438,401 cps (write via BIOS) 25,479 cps (write via DOS) 254,771 pixels/s (write via BIOS) 4.57 MB/s text 8-bit 4.56 MB/s text 16-bit 4.57 MB/s text 32-bit 1.84 MB/s graphics 8-bit 3.58 MB/s graphics 16-bit 4.51 MB/s graphics 32-bit 4.5 MB/s max video transfer rate |
1,146,599 cps (direct text 8-bit) 2,191,279 cps (direct text 16-bit) 352,206 cps (write via BIOS) 21,839 cps (write via DOS) 265,031 pixels/s (write via BIOS) 2.26 MB/s text 8-bit 4.38 MB/s text 16-bit 5.84 MB/s text 32-bit 2.25 MB/s graphics 8-bit 4.40 MB/s graphics 16-bit 5.84 MB/s graphics 32-bit 5.8 MB/s max video transfer rate |
| MonTest v1.93.0B Video Card Performance | 8,387 chars/ms (hard) 900 chars/ms (BIOS) |
10,163 chars/ms (hard) 1,577 chars/ms (BIOS) |
27,261 chars/ms (hard) 1,257 chars/ms (BIOS) |
12,744 chars/ms (hard) 1,046 chars/ms (BIOS) |
*Running UVCONFIG correctly identifies the ATI 38800-1 and sets up UNIVBE for VBE 2.0 and 3.0 extensions, but running these tests still failed.
** This test displayed a corrupted image, with just the top part of the screen being shown and flickering.
The fastest benchmarks are highlighted in bold.
A lot of DOS graphics card performance comes from the speed of the memory - this explains why the Trident card did so well in these tests with its 70ns DRAMs.
This is of course just testing in DOS (I'm not sure how best to benchmark in Windows 3.1), and I have read that VRAM performs worse in DOS and better in Windows. Despite having reasonably fast 80ns VRAM, the Diamond Stealth VRAM returns some pretty disappointing DOS benchmark results.
Setting it Up
The four DIP switches are used to tell the card what type of monitor it is connected to, define the timing of the card, and the turbo BIOS configuration. These are accessible from the card's backplate so can be changed while the card is installed and switched off. Down is 'ON'.
| SW1 / SW2 | Monitor Type | On/On = IBM 8514 or NEC Multisync 2A Off/Off = NEC Multisync 4D or 5D On/Off = Magnavox 1448 Off/On = NEC Multisync 3D |
|---|---|---|
| SW3 | Alternate Timing | On = alternate timing (used in case of incompatibilities), Off = normal timing |
| SW4 | Turbo BIOS | On = enabled, Off = disabled |
In addition, the Stealth VRAM has three jumpers:
| J1 | IRQ2 enabled/disabled | Allows the card to use this interrupt line to detect when the vertical refresh is taking place, and then avoid flicker. Note that a lot of network cards used this IRQ so if you find there is a conflict, remove this jumper from the VGA card. |
|---|---|---|
| JP5 | Amount of VRAM installed | 1-2
closed for 1 MB 2-3 closed for 512 KB |
| JP6 | 8/16-bit BIOS | Closed = a 16-bit BIOS is used (both BIOS ROMs at U13 and U14 in use) Open = an 8-bit BIOS is used (rightmost BIOS chip at U14 only is present). |
There are also solder pads for a jumper JP7 that does not have a pin header on these cards. It is marked 'JSNC'.
Downloads
Operation Manual Get in touch if you can provide this missing item! |
Original Utility Disk A 1.2 MB floppy disk image. Comprises DOS utilities, CAD drivers and installer. |
Original Utility Disk A ZIP file. Comprises DOS utilities, CAD drivers and installer. |
Windows 3.1 Drivers Windows 3.1 display driver for Stealth VRAM and Stealth 24. |
Windows 3.1 Drivers Diamond Stealth VRAM Windows 3.1 driver. 640 x 480 in 256 or 32,768 colours, 800 x 600 and 1024 x 768 in 16 or 256 colours, |
AutoCAD Driver Diamond Stealth VRAM AutoCAD driver. |
OS/2 2.1x Driver Diamond Stealth VRAM/HiColor disk for OS/2 2.1x. |
S3 SMODE Utility S3's DOS monitor configuration program for setting and loading the monitor timing information into memory |
VGA BIOS ROM Get in touch if you can provide this missing item! |
VGA BIOS ROM Thanks to Keropi on Vogons for this BIOS dump! Both U13 and U14 ICs have identical code. |
VGA BIOS ROM Get in touch if you can provide this missing item! |
VGA BIOS ROM Found on late-model Stealth VRAM cards with the 86C924 instead of 86C911. |
More Pictures
Diamond Stealth VRAM Rev. B2 (1992)