Visual Memory Unit

From Sega Retro

Visual Memory Unit
Manufacturer: Sega
Made for: Sega Dreamcast
Release Date RRP Code
Sega Dreamcast
¥2,500[1] ?
Sega Dreamcast
$? ?
Sega Dreamcast
Sega Dreamcast
Sega Dreamcast
DM 59,95[4]
Sega Dreamcast
Sega Dreamcast
$49.95[5] ?
Sega Dreamcast
R$R? ?

The Visual Memory Unit (VMU), referred to as the Visual Memory(ビジュアルメモリ) or VM (and VMS) in Japan is the de facto "memory card" for the Sega Dreamcast. While its most basic function is as a removable storage device, the VMU can also serve as an auxiliary display during normal gameplay and, through the use of additional software, it can act as a console independent of the Dreamcast.


The introduction of the VMU was considered quite radical in 1998, for as well as being a means of storing Dreamcast data, it acts as its own independent handheld "console", capitalising on a craze started by Bandai with its Tamagotchi device in late 1996. When plugged into a Dreamcast controller it can act as an extra screen (an idea that Nintendo would adopt with its Nintendo GameCube and Game Boy Advance connectors, and eventually its Wii U console), but if removed it becomes a system with its own D-Pad, A, B Mode and SLEEP buttons.

In order to function on its own, a VMU requires two CR2032 batteries, which can lead to problems. It does not require batteries in order to function within a Dreamcast controller (when the controller is connected and the system is powered on), but if the VMU lacks power it will make a high pitched warning screech during the console's bootup to alert the user.

Two VMUs can be connected together (another idea copied from Bandai, this time in its 1997 Digital Monster range, opening up new possibilities such as transferring data or playing two-player games.

Like the controllers and console, there are many different flavours of VMU in terms of colours. The colours vary depending on the market - in Japan there were many novelty VMUs, often inspired by games. In North America, translucent coloured VMUs were released, while in Europe very few coloured VMUs were sold.

The VMU technically debuted four months before the Dreamcast console, with the release of the Atsumete Godzilla: Kaijuu Dai Shuugou VMU in July 1998. As well as being a self-contained game in itself, it can be treated as a Dreamcast memory card.


While the VMU is considered an integral part of the Dreamcast console, the built-in screen and its arguably superfluous features led to a high price point when compared to memory cards of the PlayStation and Nintendo 64. Furthermore, initial shipments of Dreamcast consoles did not come with VMUs, and as the Dreamcast has no built-in memory (unlike the Sega Saturn), an extra purchase was required to save games.

Sega also did not offer an official non-screened memory card until December 2000, when the 4x Memory Card was released in Japan. The "4x" in this instance symbolises the 512kB of data available to users - standard VMUs only have 128kB, of which the widely publicised "VMU games" would usually take up most of it. In a practical sense, this meant anyone wanting to play, for example, Chao Adventure, a free VMU download in Dreamcast launch title Sonic Adventure would be better off reserving a VMU specifically for this purpose - the few remaining memory blocks after the download would not serve particularly useful for many games.

VMUs pre-date a period in video games where built-in lithium-ion rechargable batteries (seen in the Game Boy Advance SP and newer) were not the norm. This means batteries need to be replaced manually on a fairly regular basis. When a Dreamcast system is turned off, no signal is sent to the VMUs to shut down, and so operate on their own power source for a short period of time before automatically switching themselves off. If left unchecked, this can cause VMUs to drain power just by being plugged into a Dreamcast console.

Reading Save Data

When reading save data from the memory manager on the Sega Dreamcast BIOS, it will appear in this format.

Save Data
Name File Name Comment File Size
Name of the file. Name of the file as it appears within the system. Additional Information of File. Number of Blocks Used.

How each file is named and what the comments field represents depends on how the developer has written each descriptor. When reading other articles on Sonic Retro and Sega Retro, keep in mind these common symbols represented in the wiki to determine the text as these variables are likely to differ when viewing on the Memory Manager.

[##] - Number

[MM] - Month

[DD] - Day

Technical Specifications

47 mm (1.85")
80 mm (3.15")
16 mm (0.63")

  • CPU: Sanyo LC86K87 (8-bit CPU, energy saving)[6]
  • Memory: 128 KB (200 blocks)
  • Power source: Two CR2032 batteries with auto-off function[6]
  • Display: 48 dot Width x 32 dot Height resolution,[6] Monochrome
  • Display size: 37 mm (1.46 inches) Width x 26 mm (1.02 inches) Height
  • Sound: PWM sound chip,[6] 1-channel PWM sound source
  • Mass: 45g (0.099 pounds)

List of VMUs


Model No. Description Release Date Product Package Notes
HKT-7001 Atsumete Godzilla: Kaijuu Dai Shuugou
1998-07-30 HKT-7001 VM JP Godzilla.pngVMU Godzilla Green HKT-7001 Back.JPG Price: 2,500¥
HKT-7002 Visual Memory
1998-11-27 VMU JPN US.png HKT-7002 VM.png Site: [1]
Price: 2,500¥
HKT-7005 Mothra Dream Battle
1998-12-23 VMU JPN US.png HKT-7005 VM.png Notes: HKT-7002 (with software)
and figurine
Price: ?
HKT-7006 Gamera Dream Battle
1999-03-25 VMU JPN US.png HKT-7006 VM.png Notes: HKT-7002 (with software)
and figurine
Price: ?
HKT-7007-03 Visual Memory Colour Version (Aqua Blue)
ビジュアルメモリ・カラーバージョン (アクアブル)
2000-03-01 ? HKT-7007-03 VM JP AQUABLUE.PNG HKT-7007-03 VM JP AQUABLUE BOX.png Site: [2]
Price: 2,500¥
HKT-7007-04 Visual Memory Colour Version (Lime Green)
ビジュアルメモリ・カラーバージョン (ライムグリーン)
2000-03-01 ? HKT-7007-03 VM JP LIMEGREEN.PNGVMU Clear Green MK-50122 Back.JPG HKT-7007-04 VM JP LIMEGREEN BOX.png Site: [3]
Price: 2,500¥
HKT-7007-05 Visual Memory Colour Version (Passion Pink)
ビジュアルメモリ・カラーバージョン (パッションピンク)
2000-03-01 ? HKT-7007-05 VM JP PASSIONPINK.PNGVMU Passion Pink HKT-7007-05 Back.JPG HKT-7007-05 VM JP PASSIONPINK BOX.png Site: [4]
Price: 2,500¥
HKT-7007-06 Visual Memory Colour Version (Smoke)
ビジュアルメモリ・カラーバージョン (スモーク)
2000-03-01 ? HKT-7007-06 VM JP SMOKE.PNG Site: [5]
Price: 2,500¥
HKT-7007-16 Visual Memory Clear
ビジュアルメモリ クリア
2000-12-01 ? HKT-7007-16 VM JP CLEAR.jpgVMU Clear HKT-7007-16 Atrás.JPG HKT-7007-16 VM JP CLEAR BOX.pngVMU 7007-16 Clear Mint.jpg Site: [6]
Price: 2,500¥
HKT-7007-17 Virtual Memory Sonic Team version
ビジュアルメモリ ソニックチームバージョン
2000-12-21 ? VMU JP SonicTeam.jpg VMU JP SonicTeam Box.png
HKT-7007-18 SGGG (Segagaga) Virtual Memory
SGGG (セガガガ) ビジュアルメモリ
2001-03-29 HKT-7007-18 VM JP SGGG.PNG HKT-7007-18 VM JP SGGG BOX.png Note: See also Segagaga
HKT-7008-01 Super Inventor Boy Kanipan Playing Kid DCDC
超発明BOYカニパン あそんでキッドDCDC(デシデシ)
1999-04-22 HKT-7008-01 VM JP BOYKANIPAN.jpg HKT-7008-01 VM JP BOYKANIPAN box-1.PNGHKT-7008-01 VM JP BOYKANIPAN box-2.jpg Price: ?
HKT-7008-02 Giant Channel
1999-05-20 VMU JP GiantGram.jpgVMU Giant Channel HKT-7008-02 Back.JPG HKT-7008-02 VM JP GIANTCHANEL box.PNG Price: ?
HKT-7009-01 Visual Memory US Blue
ビジュアルメモリ USレッド
2001-11-01 ? VMU Blue.jpg HKT-7009-01 USBlue box.jpg Site: [7]
Price: 2,500¥
HKT-7009-02 Visual Memory US Red
ビジュアルメモリ USブルー
2001-11-01 ? VMU Red.jpg HKT-7009-02 USRed box.jpg Site: [8]
Price: 2,500¥
DD Visual Memory: Pearl White
2000-08-31 DD VM JP PEARLWHITE.png Site: Announcement
Price: 2,800¥
DD Visual Memory: Pearl Blue
2000-08-31 DD VM JP PEARLBLUE.png Site: Announcement
Price: 2,800¥
Notes: See also Special DC
model Pearl Blue
DD Visual Memory: Pearl Pink
2000-08-31 DD VM JP PEARLBLUE.JPG Site: Announcement
Price: 2,800¥
Notes: See also Special DC
model Pearl Pink
DD Visual Memory: Pure Black
2000-12-21 DD VM JP PUREBLACK.jpg DD VM JP PUREBLACK box.png Site: Announcement 1, 2
Price: 2,800¥
Notes: See also Special DC
model Pure Black
DD Visual Memory Clear Red
ビジュアルメモリ クリアレッド
2000-11-30 Site: Announcement
Note: Christmas Lottery
Might be the same as
DD Visual Memory Capcom version
ビジュアルメモリ カプコンバージョン
2000-12-22 DD VM JP CAPCOM.PNG Site: Announcement
Price: 2,800¥
DPB Visual Memory: Camouflage
1999-03-01 ? DPB VM JP CAMOUFLAGE.png DPB VM 2000POINTS box.png Price: 2000 DPB points
DPB Visual Memory: Carbon Black
1999-03-01 ? VMU JP CARBONBLACK.jpg DPB VM 2000POINTS box.png Price: 2000 DPB points
DPB Visual Memory: Wood Grain
2000-09-01 VMU JP WOODGRAIN.PNG DPB VM 2000POINTS box.png Site: Announcement
Price: 2000 DPB points
DPB Visual Memory: Leopard
2000-09-01 DPB VM JP LEOPARD.png DPB VM 2000POINTS box.png Site: Announcement
Price: 2000 DPB points
DPB Visual Memory: Marble
2000-09-01 DPB VM JP MARBLE.png DPB VM 2000POINTS box.png Site: Announcement
Price: 2000 DPB points
DPB Visual Memory: Strawberry version
2001-05-17 ? DPB VM JP STRAWBERRIES.png DPB VM 2000POINTS box.png Price: 2000 DPB points
DPB Visual Memory: Dolphin version
2001-05-17 ? DPB VM JP DOLPHINS.png DPB VM 2000POINTS box.png Price: 2000 DPB points
DPB Visual Memory: Number version
2001-05-17 ? VMU JP DirectNumber.jpg DPB VM 2000POINTS box.png Price: 2000 DPB points
Sakura Wars bundle VM
サクラ大戦 ?? 同梱
2000-05-25 VMU JP SakuraTaisen.jpg HDR-0089 bundle
Price: 6,800¥ (pack)
Sakura Wars 3 bundle VM
サクラ大戦 ?? 同梱 携帯キネマトロン型
2001-03-22 HDR-0148 Sakura Taisen VM.jpgVMU Sakura Wars 3 bundle Back.JPG HDR-0148 bundle
Price: 9,800¥ (pack)
Di Gi Charat Fantasy bundle VM
デ・ジ・キャラット ファンタジー ??
2001-09-06 T-46301M Di Gi Charat Fantasy VM.png T-46301M bundle
Price: 7,800¥ (pack)
Seaman ~Forbidden Pet~ ??
シーマン~禁断のペット~ ?? 同梱
1999-07-29 DC SEAMAN (clear) VM.PNGVMU Seaman Forbidden Pet Back.JPG Site: Announcement
Price: 34,800¥ (pack)
Hello Kitty Dreamcast Set (Blue Skeleton) bundle
Hello Kitty ドリームキャストセット (と"スケルトンブルー) 同梱
1999-11-25 DC HelloKitty (Blue) VM.PNG Site: [9], Announcement
Price: 39,800¥ (pack)
Hello Kitty Dreamcast Set (Pink Skeleton) bundle
Hello Kitty ドリームキャストセット (スケルトンピンク) 同梱
1999-11-25 DC HelloKitty (Pink) VM.PNG Site: [10], Announcement
Price: 39,800¥ (pack)
Dreamcast model: Seaman Christmas package bundle
ドリームキャスト model:SEAMAN クリスマスパッケージ 同梱
1999-12-19 DC SEAMAN (xmas) VM.PNG Price: 34,800¥ (pack)
Dreamcast CODE: Veronica LIMITEDBOX bundle
Dreamcast CODE: Veronica LIMITEDBOX 同梱
2000-02-03 DC BIOHAZARD VM.PNG Site: Announcement
Price: 34,800¥ (pack)
Dreamcast Sakura Taisen model bundle
ドリームキャスト サクラ大戦モデル 同梱
2000-12-01 DC SakuraWarsDCforInternet VM.PNG Site: [11]
Price: 25,800¥ (pack)
Sakura Wars Contest VM
  • Data in italics is not official.
  • Release dates with ? do not have a source.
  • ?? means there is something supposed to be there.


The U.S. standard VM is undistinguisable from the Japanese counterpart. However, the colour series has slightly darker casing and has grey (instead of white) buttons (notice the starking difference between the Dreamcast inscription and the button colours). The US red and US blue Japanese VMs described above are a domestic release of their overseas versions, sporting the U.S. grey buttons and are only distinct by their different packaging.

Model No Reference Product Box Notes
MK-50120 Visual Memory Unit (standard) VMU JPN US.pngVMU Branco back.jpg VMU US Box Front.jpgVMU Branco Blister back.jpg
MK-50121 Visual Memory Unit (clear blue) VMU Blue.jpg VMU Blue US Box Front.jpgVMU US Box Back.jpg
MK-50122 Visual Memory Unit (clear green) VMU Green.jpg VMU Green US Box Front.jpg a similar (or same) is included with the Holiday Gift Pack.
MK-50123 Visual Memory Unit (clear red) VMU Red.jpgVMU Clear Red MK-50123 Back.JPG VMU Red US Box Front.jpg a similar (or same) is included with the Holiday Gift Pack
MK-50124 Visual Memory Unit (clear yellow) VMU Yellow.pngVMU Yelllow Clear MK-50124 Back.JPG VMU Yellow US Box-2 Front.pngVMU Yellow US Box Front.jpgVMU amarelo Back.jpg
MK-50125 Visual Memory Unit (clear black) VMU Black.JPGVMU Black Clear MK-50125 Back.jpeg VMU Black US Box Front.jpg
  • Data in italics might not be accurate.


The standard PAL VM is different from the Japanese and U.S. devices as it does not have a spiral next to the Dreamcast inscription, and the inscription itself is made in a larger font.

Model No Reference Image Box Notes
MK-55120 Visual Memory (standard) Vmu.jpg VM PAL Box Front.jpgVM PAL Box Back.jpg

List of incompatible games

By the time the Dreamcast launched, saving games on console was well established across the gaming industry, meaning it was widely expected that any Dreamcast game would be compatible with the Visual Memory Unit (this is in contrast to the Sega Saturn, where although an internal memory saving option was available, many games were still built around a password system).

As such, unlike other Dreamcast accessories, it is more useful to list games that are not compatible with the VMU (and by extension, any Dreamcast memory card). Demos aside, the number of games which utilise a memory card is quite small and only applies to certain genres (South Park: Chef's Luv Shack for example is a multiplayer quiz game so has nothing worthwhile to "save").

Note: this list is incorrect due to missing data from individual game pages:


Physical scans

Sega Retro Average 
Publication Score Source
100 №216, p66[7]
Sega Dreamcast
Based on
1 review

Dreamcast, US

Dreamcast, BR


Sega Dreamcast
Topics Hardware Comparison | History (Development | Release | Decline and Legacy) | List of Games
Hardware Dreamcast consoles in Japan (Special) | Overseas
Add-ons Dreamcast Karaoke | Dreameye
Controllers Controller | Arcade Stick | Fishing Controller | Gun (Dream Blaster) | Race Controller | Maracas Controller | Twin Stick | Keyboard | Mouse | Third-party
Controller Add-ons Jump Pack (Third Party) | Microphone | VMU (4x Memory Card | Third Party)
Controller Connectors DC Tsunaident 123 | Dream Connection 2 in 1 | Dream Connection 4 in 1 | Dream Connection II | Super Converter 3 | Total Control | Total Control 2 | Total Control Plus | Total Control 3 | Total Control 5
Development Hardware Dev.Box | Controller Box | Controller Function Checker | Sound Box | GD-Writer | C1/C2 Checker | Dev.Cas | GD-ROM Duplicator
Online Services/Add-ons Dreamarena | SegaNet | WebTV for Dreamcast | Modem | Modular Cable | Modular Extension Cable | Broadband Adapter | Dreamphone
Connector Cables Onsei Setsuzoku Cable | RF Adapter | Scart Cable | S Tanshi Cable | Stereo AV Cable | VGA Box

Dreamcast MIDI Interface Cable | Neo Geo Pocket/Dreamcast Setsuzoku Cable | Taisen Cable

Misc. Hardware Action Replay CDX | Code Breaker | Kiosk | MP3 DC | MP3 DC Audio Player | Treamcast | Third-party
Unreleased Accessories DVD Player | Zip Drive | Swatch Access for Dreamcast | VMU MP3 Player
Arcade Variants NAOMI | Atomiswave | Sega Aurora